已知-3<b<a<-1,-2<c<-1,则(a-b)c2的取值范围是 .
(0,8)
依题意0<a-b<2,1<c2<4,
所以0<(a-b)c2<8.
It would be very safe if you _____ the door _____ to the garden. [ ]
A. fasten; led
B. will fasten; leads
C. fastened; leading
D. fastened; to lead
在妊娠期可致颅骨和面部畸形、腭裂的药是()。
A.沙利度胺
B.叶酸拮抗剂
C.孕激素
D.雄激素
E.烷化剂