“入学成熟”的提出，主要根据的是影响儿童脑力工作能力的因素中的哪个因素（）。
A、健康状况
B、性别
C、遗传
D、年龄
参考答案：D
The World Wide Web is sometimes jokingly called the World Wide Wait because it ________
be very slow. [ ]
A. should
B. must
C. will
D. can
How much is that meat, please?（）
A.Ten o'clock.
B.Ten yuan a kilo.
C.I like it very much.
D.I don't like.
