So difficult　　　 it to live in an Englishspeaking country that I was determined to learn English.

A．I have felt

B．have I felt

C．I did feel

D．did I feel

内分泌紊乱综合征多见于（）.

A.鳞状上皮细胞癌

B.肺泡细胞癌

C.腺癌

D.小细胞未分化癌

E.大细胞未分化癌