妊娠、分娩期心脏负担最重的时期是()
A.32~34周妊娠
B.第一产程
C.第二产程
D.第三产程
E.产后三天内
参考答案:C
She has _____ finished her lunch, but she hasn't washed her bowls ______. [ ]
A. already, yet
B. just, already
C. already, just
D. just, yet
有三个进程共享同一程序段,而每次只允许两个进程进入该程序段,若用PV操作同步机制,则信号量S的取值范围是( )。
A.2,1,0,-1
B.3,2,1,0
C.2,1,0,-1,-2
D.1,0,-1,-2