7.Convenient ______ plastic bags are for people, they will cause white pollution.

A. as B. although

C. since D. while

【答案】A

【解析】

【详解】考查形式倒装句。句意：对人们来说尽管塑料袋很方便，但它们会导致白色污染。句中形式倒装句"Convenient as plastic bags are for people"相当于让步状语从句"Although plastic bags are convenient for people"，故A项正确。

【点睛】本句考查了as引导让步状语从句倒装的用法：具体如下：

名词 + as / though + 主语 + 动词

King as he was，he was unhappy. 他虽是国王，但他并不幸福。

Child as he is，he knows to help other. 他虽是个孩子，却知道帮助别人。

【说明】其中的动词通常为系动词，也就是说位于句首的名词是其后系动词的表语。另外，要特别注意位于句首的名词前习惯上不用冠词，即使其前有形容词修饰也不用冠词。比较：

Boy as he is， he likes to play with girls.=Though he is a boy，he likes to play with girls.

他虽是男孩，却喜欢与女孩子玩。

Strong man as he is，General Botha has been severely put to the test during the past few weeks.= Though he is a strong man， General Botha has been severely put to the test during the past few weeks. 波赛将军虽然坚强，但在过去的数周里也受到了严峻的考验。

二、形容词 + as / though + 主语 + 动词

Successful as he is，he is not proud. 他虽然成功，但不骄傲。

Improbable as it seems，it's true. 虽然看起来不太可能，但却是真的。

Stupid as it sounds，I was so in love with her that I believed her.

尽管听起来很愚蠢，我是如此爱她竟然相信了她的话。

Patient as he was，he didn't like waiting that long. 他虽说有耐心，也不愿等这么长。

Beautiful though the necklace was，we thought it was over-priced.

那条项链虽然很漂亮，我们认为价钱太高。