完形填空。
It is Sunday morning. The students are going to the __⑴___. Lily and Lucy like animals__⑵__.They get up very ___⑶__ in the morning. After __⑷___ they go to school. The students ___⑸_ at the school gate. They go there ____⑹___. Miss Gao goes ____⑺___ them.
There are many kinds of __⑻____ in the zoo. The biggest one is ___⑼___. But they can’t see any cats.
The students ___⑽__ the zoo at four in the afternoon. Lily and Lucy get home at about five. They have a very good time.
( )⑴A.cinema B. zoo C. factory D. hospital
( )⑵A.very well B. very good C. very much D. very nice
( ) ⑶A.early B. late C. earlier D. later
( )⑷A.supper B. lunch C. breakfast D. meal
( )⑸A.see B. watch C. look D. meet
( )⑹A.by foot B. on foot C.by feet D. on feet
( )⑺A. for B. and C. with D. of
( )⑻A. animals B. birds C. cats D. boats
( )⑼A. a monkey B. a bird C. a tiger D.an elephant
( )⑽A. get to B. go to C. leave D. like
打点计时器是一种使用 （填“交”或“直”）流电源的计时仪器．如图所示是打点计时器测定匀加速直线运动的加速度时得到的一条纸带，测出AB=1.2cm，AC=3.6cm，AD=7.2cm，计数点A、B、C、D中，每相邻的两个计数点之间有四个小点未画出，则运动物体的加速度a= m/s2，打B点时运动物体的速度vB= m/s．
如图甲所示的电路中，D为二极管（正向电阻为零，反向电阻为无穷大），R1=R2=4Ω，R3=6Ω当在AB间加上如图乙所示的交流电压时，在0～1×10﹣2s时间内通过R1的电流 ；1s内电阻R3所消耗的电能 ．
如图所示，使闭合矩形线圈在匀强磁场中绕垂直于磁场方向的转轴匀速转动，在线圈中就会产生交流电．已知磁场的磁感应强度为B，线圈abcd面积为S，线圈转动的角速度为ω．当线圈转到如图位置时，线圈中的感应电动势为 ；当线圈从图示位置转过90°时，线圈中的感应电动势为 ．
闭合线圈在匀强磁场中匀速转动，转速为240r/min，若线圈平面转至于磁场平行时的电动势为2V，则从中性面开始计时，所产生的交流电动势的表达式为e= V；从中性面起经
，交流电动势的大小为 V．
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