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：

Courageous people think quickly and act without hesitation.

Courageous people think quickly and act without hesitation.A．complaint B．conside

分类：卫生类题型：单选题

What were the effects of the decision she made?A．reasons B．results C．causes D．ba

分类：卫生类题型：单选题

Who brought the Frenchmen's neckwear to Britain?A．Tony Blair. B．Charles ll. C．Ji

分类：卫生类题型：单选题

A red flag was placed there as a token of danger.A．sign B．substitute C．proof D．t

分类：卫生类题型：单选题

某人拥有一套住房，若出租，则年租赁净收入为2万元。若其拟出售此住房，并要求年收益率为12％时，假设收益年期无限，则此住房的净销售收入应为（　）万元。A．14．5

分类：卫生类题型：单选题