关于更换变压器的回收年限，一般考虑当计算的回收年限小于5年时，变压器()更新为宜。
A．应
B．应立即
C．不应
D．不可
参考答案：B
No sooner ____ to the cinema ____ the film began. [ ]
A. had he got, than
B. he had got, when
C. did he get, than
D. had he got, when
血中Hb含量低于多少时，即使重度缺氧，亦难发现发绀（）
A.<50g/L
B.<60g/L
C.<70g/L
D.<80g/L
E.<90g/L
