如图，∠MON＝30°，点A1在射线OM上，过点A1作A1B1⊥OM交射线ON于点B1，将△A1OB1沿A1B1折叠得到△A1A2B1，点A2落在射线OM上；过点A2作A2B2⊥OM交射线ON于点B2，将△A2OB2沿A2B2折叠得到△A2A3B2，点A2落在射线OM上；…按此作法进行下去，在∠MON内部作射线OH，分别与A1B1，A2B2，A3B3，…，AnBn交于点P1，P2，P3，…Pn，又分别与A2B1，A3B2，A4B3，…，An＋1Bn，交于点Q1，Q2，Q3，…，Qn．若点P1为线段A1B1的中点，OA1＝√3，则四边形AnPnQnAn＋1的面积为___________________（用含有n的式子表示）．
The family ___ at the lunch table when someone came to tell them what had happened at ___.
I called you just now, but you weren't in. Sorry, I ______ the reading room.
I will give ______ students ______ minutes for them to finish their exercise
Every morning, WE are asked ______ taken our temperatures.
She ______ his number in the phone book to make sure that she had got it right.
I will spend as much time as I ______ the lesson.
He's never stolen anything before, ______ he? ______. It's his third time to be taken to police station.
Has Jack finished his homework yet? I've no idea, But he ______ it the whole afternoon.
______did you sleep last night? I was reading too late to fall asleep.
Have you ______ your father recently? No. He doesn't often write to me.
