问题 选择题
如图所示,矩形线圈有N匝,长为a,宽为b,每匝线圈电阻为R,从磁感应强度为B的匀强磁场中以速度v匀速拉出来,那么,产生的感应电动势和流经线圈中的感应电流的大小应为(  )

A.E=Bav,

B.E=NBav,

C.E=Bav,

D.E=NBav,

答案

答案:D

写作题
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Lulu is a brave pet in our shelter.

As you know, there are a lot of forest fires during the summer season.Many forests are badly 1 by fire each year.Not far from our shelter, a forest caught fire during this hot summer.We were in a heat wave which had been  2 for three days.

Lulu rushed towards the forest where flames sent out a terrible 3 .I no longer had any hope that Lulu would come  4 to the shelter.In fact, I was waiting for the firemen to announce his 5 in the forest, when suddenly, a fireman burst into my shelter and  6  me that my dog Lulu had  7 to save four kittens who were trapped by the flames.According to the fireman, Lulu seized the kittens, one by one moving them to a  8 place.I immediately accompanied the fireman to the forest to  9 the rescued kittens.When we arrived at the  10 of the incident, we found Lulu was not  11 .Then we heard the  12 of a dog came from the forest barking furiously.I  13 it was my dog Lulu.The fireman followed the tracks of the dog until we found him barking  14 by the side of an injured fireman who was lying on the ground and desperately 15 rescue.Thanks to Lulu, four kittens and a fireman were saved.

That day, I was very 16 of Lulu for his two heroic  17 toward the kittens and the fireman.Lulu showed much compassion (同情) for both animals  18 him and for a human being who was trying to  19 the fire with his colleagues.

This true story of genuine love and compassion shows us that pets are loving,  20 and compassionate.We should love and protect them.One day they could do us a good turn.

1.A.damaged              B.destroyed               C.wounded         D.hurt

2.A.taking on          B.coming on        C.going on              D.keeping on

3.A.heat                      B.energy             C.fever               D.burn

4.A.by                       B.round              C.up                     D.back

5.A.return               B.honor                C.death               D.action

6.A.announced        B.informed             C.communicated        D.claimed

7.A.tried                      B.wanted               C.managed              D.failed

8.A.safe                   B.safer                      C.lonely                    D.beautiful

9.A.pick out               B.pick up              C.bring on             D.bring up

10.A.scene                 B.position         C.situation          D.view

11.A.here                B.out                    C.in                          D.there

12.A.voice                     B.noise                     C.accent              D.sound

13.A.acknowledged        B.recognized      C.heard                     D.listened

14.A.heavily              B.strongly             C.loudly                  D.happily

15.A.waiting for         B.waiting on              C.asking for             D.looking for

16.A.surprised         B.satisfied             C.shamed              D.proud

17.A.things                    B.actions               C.dos                    D.reactions

18.A.as                    B.like                   C.for                        D.to

19.A.put off               B.put away       C.put up                    D.put out

20.A.careful               B.careless         C.caring              D.carefree