胎儿缺氧早期的胎心率为()
A.110~125次/分
B.130~160次/分
C.160~180次/分
D.180~200次/分
E.200~220次/分
参考答案:C
Mingming is writing a letter ______________ his mother. [ ]
A. of
B. to
C. for
在使用Dim语句定义数组时,在缺省情况下数组下标的下限为_________。