正常正循环时,井底压力等于()。
A、井液压力+环空流体的摩阻压力
B、井液压力+油管内流体的摩阻压力
C、环空流体的摩阻压力
D、油管内流体的摩阻压力
参考答案:A
--- I saw the Smiths at West Beijing Station this afternoon.
--- You __________. They are still on holiday in Hawaii.
A.mustn't have
B.shouldn't
C.couldn't have
D.needn't
下图能正确表示基因分离定律实质的是()。
A.A
B.B
C.C
D.D