[讨论]GWD17-Q21

1. but not with other nonhospital services where 20 percent of the costs must be paid by beneficiaries
2. but not of other nonhospital services, making beneficiaries pay 20 percent of the costs
3. but not of other nonhospital services, for which beneficiaries must pay 20 percent of the costs
4. which is unlike other nonhospital services in that 20 percent of the costs must be paid by beneficiaries
5. which is unlike other nonhospital services that make beneficiaries pay 20 percent of the costs

答案是C

在C和D上犹豫了很久还是选了D，

因为C的but之前有个逗号，应该but连接后面的是一个句子，但是but后面的省略不应该省去谓语部分（这里也不是两个be，省略后面那个的情况），所以虽然C后面的主动语态和定从都很好，还是没有选。难道并列句的省略可以主谓都省略而只剩下否定词和介词短语么？我有比较清楚的影响，这种省略是错误的。

D的which就直接修饰前面的home health care应该没什么问题，跳跃修饰的时情况很少，也没出现过因为which可能跳跃修饰所以出现的修饰对象不清楚的错误题目。in that虽然不是很好感觉，但是还是可以用作替代because的，被动语态不是很好，毕竟还是有by说明执行对象，所以最后还是选了D。

我的问题就是对，but not省略的正确和错误的判断，请大家指点一二。

prep35.   (26325-!-item-!-188;#058&002592)

In laboratory rats, a low dose of aspirin usually suffices to block production of thromboxane, which is a substance that promotes blood clotting, but not seriously interfering with the production of prostacyclin, which prevents clotting.

(A) which is a substance that promotes blood clotting, but not seriously interfering

(B) a substance that promotes blood clotting, but not seriously interfering

(C) a substance that promotes blood clotting, but does not seriously interfere

(D) which is a substance to promote blood clotting, but does not seriously interfere

(E) which is a substance that promotes blood clotting, but not a serious interference

答案是C，这里的but not就不能省略does

OG也有一题，是这个问题，但是答案是把but not 改成了rather than

供参考：

http://forum.chasedream.com/dispbbs.asp?BoardID=23&ID=43230

没人帮忙么？自己up一下

前面大N在这个帖子里面已经很深入的讨论过了逗号的问题。我自己的体会是一切以逻辑意思表达清楚无歧义为最高准则，并没有一定之规。

GWD17-Q21我也认为but前面的逗号去掉比较好，但是这里的逗号不是致命的错误，逻辑意思还是很清楚的，所以还是建议选C

3x，不过即使没有逗号这个but not中的not（副词）使用来修饰动词的（修饰动词的时候不能省略助动词吧），不能修饰名词，在OG里面修饰名词的时候就改成了rather than啊。

还是不明白啊