在我国铁路运输中，团体旅客要求退票，必须在（）办理。A．开车前 B．开车后2小时以内

---Do you feel like ______ or shall we go by bus?

---I prefer _______ , but we had better take a taxi, for time is short.

A．to walk; walking

B．walking; to walk

C．walking; walking

D．to walk; to walk

The following questions present a sentence, part of which or all of which is underlined. Beneath the sentence, you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise choose one of the others.

These questions test correctness and effectiveness of expression. In choosing your answer, follow the requirements of standard written English; that is, pay attention to grammar, choice of words, and sentence construction. Choose the answer that produces the most effective sentence; this answer should be clear and exact, without awkwardness, ambiguity, redundancy, or grammatical error.

Atmospheric scientists in recent years have observed increasing concentrations of chlorofluorocarbons in the tertiary layer of the stratosphere, findings consistent with the documented growth in chlorofluorocarbon emissions from industrial activity.（）

A. findings consistent with the documented growth in chlorofluorocarbon emissions from industrial activity

B. which are consistent with the documented growth in chlorofluorocarbon emissions from industrial activity

C. a finding consistent with growth in chlorofluorocarbon emissions from industrial activity, as documented

D. finding documented growth consistent with chlorofluorocarbon emissions from industrial activity

E. which findings are consistent with industrial activity’s documented growth in chlorofluorocarbon emissions

下面关于WindowsServer2003系统DNS服务的说法，错误的是（）。

A．DNS服务提供域名到IP地址的查询服务 

B．利用DNS服务可以通过IP地址查找到对应的域名 

C．对于给定域名的多次查询，DNS服务器返回的IP地址可能是不同的 

D．DNS服务采用的传输层协议是TCP

以消旋体给药，但其药效成分为（S）-（+）-构型的药物是（）

A.别嘌醇

B.布洛芬

C.吲哚美辛

D.双氯芬酸钠

E.塞来昔布

什么叫直接雷过电压？