女性肺癌相对多见的是（）
A.鳞癌
B.腺癌
C.小细胞癌
D.大细胞癌
E.混合型癌
参考答案：B
We went through a period _____ communications were very difficult in the rural areas. [ ]
A. which
B. whose
C. in which
D. with which
肺炎链球菌的主要致病因素是（）
A.鞭毛
B.菌毛
C.荚膜
D.外毒素
E.内毒素
