预防小儿维生素D缺乏性佝偻病,每日口服维生素D多少单位()
A.100IU
B.200IU
C.300IU
D.400IU
E.500IU
参考答案:D
— Did Jim ride his bike to school this morning?
— He _____ come to school by bike. He hasn't found his bike yet.[ ]
A. may
B. mustn't
C. can
D. can't
t为int类型,进入下面的循环之前,t的值为0。 while(t=1){...} 则以下叙述中,正确的是( )。
A.循环控制表达式的值为0
B.循环控制表达式的值为1
C.循环控制表达式不合法
D.以上说法都不对