影响我国降水的行星尺度系统有几种()
A.2
B.3
C.4
D.5
参考答案:C
妊娠几周后,B型超声可作为产前诊断项目()
A.5周
B.12周
C.16周
D.24周
E.28周
No matter what they say, I’ll ___ my opinion.
A.stick to
B.persist in
C.insist on
D.hold up