You felt unhappy yesterday, _____? [ ]
A. didn't you
B. did you
C. don't you
D. do you
答案:A
下列哪种构造层次不属于不保温屋面()
A.结构层
B.找平层
C.隔汽层
D.保护层
吸吮反射消失时间为生后
A.2个月
B.3个月
C.4个月
D.5个月
E.6个月