在Web页面上使用关键字进行搜索，首先单击（）出现下拉选单后选择查找。
参考答案：编辑
—Is Nancy knocking at the door?
—No, it ________ be Nancy. She has gone to Guangzhou. [ ]
A. can't
B. mustn't
C. won't
HTTPS采用______协议实现安全网站访问。
A．SSS B．IPSec C．PGP D．SET
