女性不孕原因排在首位的是（）。

A.不排卵

B.输卵管因素

C.慢性宫颈炎

D.卵巢囊肿

E.慢性盆腔炎

—What was your    brother doing at this time yesterday? 

—He was reading a magazine _________ I was  writing an e-mail at home.[ ]

A. as soon as              

B. after

C. until                    

D. while