单选题：The cause of AIDS remains a mystery to researchers．

题目内容：

The cause of AIDS remains a mystery to researchers． A．Right
B．Wrong
C．Not mentioned

参考答案：

答案解析：

How did the doctors respond to Mr．Cousins’ illness?

How did the doctors respond to Mr．Cousins’ illness?A．They promised to cure hi B．

分类：卫生类题型：单选题

What did he do to make her happy?A．He studied much harde B．He often took her for

分类：卫生类题型：单选题

Since ancient times people have found various ways to preserve meat．A．eat B．cook

分类：卫生类题型：单选题

John is crazy about pop music．A．sorry B．mad C．conceded D．worried

分类：卫生类题型：单选题

分类：卫生类题型：单选题