阅读下列案例,并根据教学过程的基本阶段加以分析。?
这是一堂科学课,课程题目为“植物的根如何吸水”。?
开始上课后,老师很神秘地说:“我做了一个有趣的实验,你们睁大眼睛好好观察。看看谁能分析出其中的道理来。”?
老师说着就拿出了两个瓶子,里边是分别浸泡在清水和盐水里的萝卜,然后老师从液体中拿出萝卜,对同学们说:“这根萝卜是被清水浸泡过的,而这根是被盐水浸泡过的。”同学们仔细观察后发现:泡过清水的萝卜变水灵了,而泡过盐水的萝卜则变蔫了。?
老师要求大家分小组讨论:为什么会发生这个变化?并提示大家,这跟水分的流向有关。?
于是,同学们在老师的启发引导下,七嘴八舌地议论开了。最后,大家得出的结论是:泡过清水的萝卜吸水了,因为萝卜细胞液浓度大于清水,水分向萝卜渗透;泡过盐水的萝卜失水了,因为萝卜细胞液浓度小于盐水的,水分从萝卜中外渗出来。?
接着,老师引导大家总结出水的渗透规律:水分总是从浓度小的溶液向浓度大的溶液渗透。植物的根吸水就是因为植物的细胞液浓度大于土壤里的溶液。?
教学结束时,老师对实验结论进行了总结,要求大家对“植物的根吸水”的原理整理课堂笔记。?
最后,老师布置课外作业,要求大家研究一下:学校校园里有几株花出现烧根现象,这是什么原因导致的?应该如何处理呢?再进一步思考,盐碱地为什么长不好庄稼?又该如何处理呢?
教学过程大致分为五个阶段,该老师较好地遵循了教学过程中学生认识的特殊性规律,取得了较好的效果。
(3分)
(1)激发学习动机:老师很神秘地说自己做了一个有趣的实验,让学生睁大眼睛好好观察,激发了学生学习的兴趣、求知欲等。(3分)
(2)感知阶段:老师拿出浸泡在清水和盐水里的萝h,让学生观察两者的区别,使学生对水分的流向、细胞液浓度有了初步的感性认识。(3分)
(3)理解阶段:老师通过提示和引导,使学生明白植物的根吸水的原因,进一步掌握了出水的渗透规律。(2分)
(4)巩固阶段:老师再次总结结论并要求学生对“植物的根吸水”的原理整理课堂笔记,巩固了所学内容。(2分)
(5)运用阶段:老师通过布置作业,要求学生研究、思考实际生活中的问题。(2分)
学校将组织一次英语演讲比赛,打算邀请外教(John)来做评委。请你(Li Yuan)给他写一封e—mail,内容包括:?
·邀请他担任评委(judge);?
·告知他比赛安排(如:时间、地点等);?
·希望他赛后进行点评;?
·期待他能接受邀请。
A.I am free on Sunday.
B.See you then!
C.Where are you planning to go?
D.No,thanks.
E.I need a break!
F.Would you like to join us?
G.That is a lovely place.
H.When shall we leave?
Daniel:How are you doing,Linda?
Linda:To be honest,I am really tired of my
Heahh care experts have long drawn attention to the problems of eating too much sah.There isstrong evidence that a diet high in salt can lead to raised blood pressure.Since high blood pressure is amajor factor in heart disease.it makes sense to cut down on the salt people eat.?
In the past,food contained very little salt,and people added it to their food at the table.Very fewpeople ?add ?salt this ?way ?nowadays.However,the ?salt ?content ?of processed ?foods has ?gone ?updramatically.It’s now estimated that over three.quarters of the salt in the average diet comes fromprocessed foods,eaten without our being aware of it.?
Salt is added to food partly to extend shelf-life.but more often it’s dropped in to make up for theflavor lost in the manufacturing process.This is especially true of ready meals and highly processedfoods.but it’s also true of such basic food as biscuits,soups,and even bread.Much mass—producedbread,for instance.contains so much salt.half a gram for every hundred grams of bread--that it’sofficiallv classified bv the UK government as high——salt food.Salt has to be added to the bread becausefast Droduetion cuts down the time for the flavor to develop.Without added salt,the bread would tastelike paper.?
In the UK,the government has launched a campaign to cut down on the salt people eat.The UK Food Standards Agency argues that nearly half of the UK’s population eat too much salt—9.5 9 a day onaverage.Its aim is to bring down the average t0 69 a day.The idea is to cut the salt content in 85 keyfood categories such as bread.meat.and cakes.?
?What is the passage mainly about?
Heahh care experts have long drawn attention to the problems of eating too much sah.There isstrong evidence that a diet high in salt can lead to raised blood pressure.Since high blood pressure is amajor factor in heart disease.it makes sense to cut down on the salt people eat.?
In the past,food contained very little salt,and people added it to their food at the table.Very fewpeople ?add ?salt this ?way ?nowadays.However,the ?salt ?content ?of processed ?foods has ?gone ?updramatically.It’s now estimated that over three.quarters of the salt in the average diet comes fromprocessed foods,eaten without our being aware of it.?
Salt is added to food partly to extend shelf-life.but more often it’s dropped in to make up for theflavor lost in the manufacturing process.This is especially true of ready meals and highly processedfoods.but it’s also true of such basic food as biscuits,soups,and even bread.Much mass—producedbread,for instance.contains so much salt.half a gram for every hundred grams of bread--that it’sofficiallv classified bv the UK government as high——salt food.Salt has to be added to the bread becausefast Droduetion cuts down the time for the flavor to develop.Without added salt,the bread would tastelike paper.?
In the UK,the government has launched a campaign to cut down on the salt people eat.The UK Food Standards Agency argues that nearly half of the UK’s population eat too much salt—9.5 9 a day onaverage.Its aim is to bring down the average t0 69 a day.The idea is to cut the salt content in 85 keyfood categories such as bread.meat.and cakes.?
Which of the following is classified as high—salt food by the UK government?
Heahh care experts have long drawn attention to the problems of eating too much sah.There isstrong evidence that a diet high in salt can lead to raised blood pressure.Since high blood pressure is amajor factor in heart disease.it makes sense to cut down on the salt people eat.?
In the past,food contained very little salt,and people added it to their food at the table.Very fewpeople ?add ?salt this ?way ?nowadays.However,the ?salt ?content ?of processed ?foods has ?gone ?updramatically.It’s now estimated that over three.quarters of the salt in the average diet comes fromprocessed foods,eaten without our being aware of it.?
Salt is added to food partly to extend shelf-life.but more often it’s dropped in to make up for theflavor lost in the manufacturing process.This is especially true of ready meals and highly processedfoods.but it’s also true of such basic food as biscuits,soups,and even bread.Much mass—producedbread,for instance.contains so much salt.half a gram for every hundred grams of bread--that it’sofficiallv classified bv the UK government as high——salt food.Salt has to be added to the bread becausefast Droduetion cuts down the time for the flavor to develop.Without added salt,the bread would tastelike paper.?
In the UK,the government has launched a campaign to cut down on the salt people eat.The UK Food Standards Agency argues that nearly half of the UK’s population eat too much salt—9.5 9 a day onaverage.Its aim is to bring down the average t0 69 a day.The idea is to cut the salt content in 85 keyfood categories such as bread.meat.and cakes.?
What can be inferred about people’s use of salt in the past?
Heahh care experts have long drawn attention to the problems of eating too much sah.There isstrong evidence that a diet high in salt can lead to raised blood pressure.Since high blood pressure is amajor factor in heart disease.it makes sense to cut down on the salt people eat.?
In the past,food contained very little salt,and people added it to their food at the table.Very fewpeople ?add ?salt this ?way ?nowadays.However,the ?salt ?content ?of processed ?foods has ?gone ?updramatically.It’s now estimated that over three.quarters of the salt in the average diet comes fromprocessed foods,eaten without our being aware of it.?
Salt is added to food partly to extend shelf-life.but more often it’s dropped in to make up for theflavor lost in the manufacturing process.This is especially true of ready meals and highly processedfoods.but it’s also true of such basic food as biscuits,soups,and even bread.Much mass—producedbread,for instance.contains so much salt.half a gram for every hundred grams of bread--that it’sofficiallv classified bv the UK government as high——salt food.Salt has to be added to the bread becausefast Droduetion cuts down the time for the flavor to develop.Without added salt,the bread would tastelike paper.?
In the UK,the government has launched a campaign to cut down on the salt people eat.The UK Food Standards Agency argues that nearly half of the UK’s population eat too much salt—9.5 9 a day onaverage.Its aim is to bring down the average t0 69 a day.The idea is to cut the salt content in 85 keyfood categories such as bread.meat.and cakes.?
What is the main reason for reducing salt in food?
My boyfriend really enjoyed canoeing (划独木舟), and it took me a while to finally persuade himto take me on a canoe trip. Despite his great skill, he was nervous about my safety and described manyterrible situations that could happen. "They could also not happen," I said. I wanted to prove that I wastough and capable of adventuring.?
This would be a romantic adventure. We would row the canoe on the lake under a beautiful bluesky. I was confident it would all go according to plan.?
It did not go as planned. Instead,?it all went downhill. We hit a headwind (逆风). The flies werethe worst. An unknown animal outside our tent in the night forced us to get up twice to scare it away.We walked through knee-deep mud; we moved around so many fallen trees that we lost the wayfrequently. We had an unexpected thunderstorm on our second night. We hid in our tent from the bugs(虫子), too tired and bitten to even hold each other. When we were finally back in the car, my skinwas hot and angry with bug bites, I had barely slept in 72 hours and I had an injury on my forehead fromhitting it on the canoe.?
Yet I realized that I wanted to do it all again. Because I swam in a lake so warm it felt like asummer pool. ?I ate lunch on an island with the most beautiful pine trees. ?I' d also never beforeappreciated how thunder can make the ground tremble. I know why my boyfriend loves canoeing somuch. It' s for the challenge, the space, and the beauty of moving forward with your own two hands ina place of natural wonder. He didn' t say "I love you. " He said I was a good partner. I' ve foundsomething that I really like to do. That' s the more important thing.?
What would be the best title for the passage?
My boyfriend really enjoyed canoeing (划独木舟), and it took me a while to finally persuade himto take me on a canoe trip. Despite his great skill, he was nervous about my safety and described manyterrible situations that could happen. "They could also not happen," I said. I wanted to prove that I wastough and capable of adventuring.?
This would be a romantic adventure. We would row the canoe on the lake under a beautiful bluesky. I was confident it would all go according to plan.?
It did not go as planned. Instead,?it all went downhill. We hit a headwind (逆风). The flies werethe worst. An unknown animal outside our tent in the night forced us to get up twice to scare it away.We walked through knee-deep mud; we moved around so many fallen trees that we lost the wayfrequently. We had an unexpected thunderstorm on our second night. We hid in our tent from the bugs(虫子), too tired and bitten to even hold each other. When we were finally back in the car, my skinwas hot and angry with bug bites, I had barely slept in 72 hours and I had an injury on my forehead fromhitting it on the canoe.?
Yet I realized that I wanted to do it all again. Because I swam in a lake so warm it felt like asummer pool. ?I ate lunch on an island with the most beautiful pine trees. ?I' d also never beforeappreciated how thunder can make the ground tremble. I know why my boyfriend loves canoeing somuch. It' s for the challenge, the space, and the beauty of moving forward with your own two hands ina place of natural wonder. He didn' t say "I love you. " He said I was a good partner. I' ve foundsomething that I really like to do. That' s the more important thing.?
Which of the following happened during their canoe trip?
My boyfriend really enjoyed canoeing (划独木舟), and it took me a while to finally persuade himto take me on a canoe trip. Despite his great skill, he was nervous about my safety and described manyterrible situations that could happen. "They could also not happen," I said. I wanted to prove that I wastough and capable of adventuring.?
This would be a romantic adventure. We would row the canoe on the lake under a beautiful bluesky. I was confident it would all go according to plan.?
It did not go as planned. Instead,?it all went downhill. We hit a headwind (逆风). The flies werethe worst. An unknown animal outside our tent in the night forced us to get up twice to scare it away.We walked through knee-deep mud; we moved around so many fallen trees that we lost the wayfrequently. We had an unexpected thunderstorm on our second night. We hid in our tent from the bugs(虫子), too tired and bitten to even hold each other. When we were finally back in the car, my skinwas hot and angry with bug bites, I had barely slept in 72 hours and I had an injury on my forehead fromhitting it on the canoe.?
Yet I realized that I wanted to do it all again. Because I swam in a lake so warm it felt like asummer pool. ?I ate lunch on an island with the most beautiful pine trees. ?I' d also never beforeappreciated how thunder can make the ground tremble. I know why my boyfriend loves canoeing somuch. It' s for the challenge, the space, and the beauty of moving forward with your own two hands ina place of natural wonder. He didn' t say "I love you. " He said I was a good partner. I' ve foundsomething that I really like to do. That' s the more important thing.?
What does the sentence“it all went downhill”in Paragraph 3 mean?
My boyfriend really enjoyed canoeing (划独木舟), and it took me a while to finally persuade himto take me on a canoe trip. Despite his great skill, he was nervous about my safety and described manyterrible situations that could happen. "They could also not happen," I said. I wanted to prove that I wastough and capable of adventuring.?
This would be a romantic adventure. We would row the canoe on the lake under a beautiful bluesky. I was confident it would all go according to plan.?
It did not go as planned. Instead,?it all went downhill. We hit a headwind (逆风). The flies werethe worst. An unknown animal outside our tent in the night forced us to get up twice to scare it away.We walked through knee-deep mud; we moved around so many fallen trees that we lost the wayfrequently. We had an unexpected thunderstorm on our second night. We hid in our tent from the bugs(虫子), too tired and bitten to even hold each other. When we were finally back in the car, my skinwas hot and angry with bug bites, I had barely slept in 72 hours and I had an injury on my forehead fromhitting it on the canoe.?
Yet I realized that I wanted to do it all again. Because I swam in a lake so warm it felt like asummer pool. ?I ate lunch on an island with the most beautiful pine trees. ?I' d also never beforeappreciated how thunder can make the ground tremble. I know why my boyfriend loves canoeing somuch. It' s for the challenge, the space, and the beauty of moving forward with your own two hands ina place of natural wonder. He didn' t say "I love you. " He said I was a good partner. I' ve foundsomething that I really like to do. That' s the more important thing.?
Why did the writer want to have a canoe trip with her boyfriend?