VHDL常用的库是（）。
A.IEEE
B.STD
C.WORK
D.PACKAGE
参考答案：A
The policeman asked the child _____ cross the street _____ the traffic lights turned green. [ ]
A. not, when
B. don't, before
C. not to, until
D. not, until
第一产程活跃期的减速期是指宫口扩张（）
A.9～10cm
B.3～10cm
C.7～10cm
D.5～10cm
E.8～10cm
