John _____ interested in Chinese two years ago.[ ]
A. is
B. became
C. are
D. were
答案:B
将一个铜球放在容器底部,然后向容器内注水,则铜球所受的浮力( )
A.随着注水量的增加而增大
B.随着注水量的增加而减少
C.与注水量的多少无关
D.开始时随着注水量的增加而增大,水没过铜球后,浮力的大小不再变化
痘疹用温补学派的创始人是()
A.钱乙
B.董汲
C.陈文中
D.曾世荣
E.张琰