网上调查（）适合对关键问题的定性调查研究。
A.电子邮件法
B.站点法
C.视讯会议法
D.随机IP法
参考答案：C
The secretary worked late into the night, _______ a long speech for the international conference. [ ]
A. to prepare
B. prepared
C. preparing
D. was preparing
不含肌上皮细胞的肿瘤为
A．黏液表皮样癌
B．多形性腺瘤
C．腺样囊性癌
D．腺淋巴瘤
E．肌上皮瘤
