A:运动的平均速度大小为12v
B:平滑位移大小为qRBL
C:产生的焦耳热为qBLv
D:受到的最大安培力大小为B2L2vRsinθ
⑴ ____ A. Beijing is a great city.
⑵ ____ B. Time to go back to school.
⑶ ____ C. Don't forget to take some pictures.
⑷ ____ D. I'm putting on my new coat.
⑸ ____ E. What a fun trip!
—Must he finish the work before lunch?
— ___________. He can do it in the afternoon.