单选题：It remains a puzzle about why our outermost planet exists.

题目内容：

It remains a puzzle about why our outermost planet exists. A．problem
B．mystery
C．question
D．point

参考答案：

答案解析：

Chirac takes a stand similar to Blair's on Africa and climat

Chirac takes a stand similar to Blair's on Africa and climate change.A．Right B．

分类：理工类题型：单选题

Professional baseball teams can continue to play for a long period of time in t

分类：理工类题型：单选题

This poem depicts the beautiful scenery of a small town in the South.A．describe

分类：理工类题型：单选题

He impressed all his colleagues as a vigorous man in the prime of his career.A．

分类：理工类题型：单选题

The rules are too rigid to allow for human error.A．general B．complex C．inflexibl

分类：理工类题型：单选题