下列哪些情况易发生新生儿肺透明膜病（）
A.双胎第一胎
B.早产儿
C.糖尿病母亲婴儿
D.围产期窒息
E.剖宫产
参考答案：B, C, D, E
When I dropped in, Dr Smith _____, so we only had time for a few words. [ ]
A. just left
B. was just leaving
C. has just left
D. had just left
ISDN接入Internet时所连接的接口主要有（）。
A.RS-232接口
B.S/T接口
C.U接口
D.Lpt1接口
