糕点工厂空气浮游微生物主要是（）.
A.青霉素
B.大肠菌群
C.霉菌
D.乳酸菌
参考答案：B
-_________
-I can't sleep well because my brother plays his CDs too loud. [ ]
A. What's wrong?
B. How do you sleep?
C. You should sleep well.
D. How are you feeling?
我国规定老年期开始于
A．55岁以后
B．60岁以后
C．70岁以后
D．65岁以后
E．75岁以后
