mary1

对你的第一个问题有一点心得，想跟大家探讨一下。

对于什么时候省略助动词，什么时候不省的问题，我看OG的时候总结了一下，基本上觉得是这样：省略之后，有时候会造成歧义，不知道句子保留的是从句的主语还是宾语，这种时候就一定不能省；反之，如果没有这种歧义，就可以省。比如：

224. Inuits of the Bering Sea were in isolation from contact with Europeans longer than Aleuts or Inuits of the North Pacific and northern Alaska.

(A) in isolation from contact with Europeans longer than

(B) isolated from contact with Europeans longer than

(C) in isolation from contact with Europeans longer than were

(D) isolated from contact with Europeans longer than were（D）

(E) in isolation and without contacts with Europeans longer than

The phrasing of the comparisons in choices A, B, and E is incomplete, so the comparisons are ambiguous: because longer than could be followed by either from or were, it is unclear whether Inuits of the Bering Sea were isolated from Europeans longer than from the other Native American groups, or whether they were isolated from Europeans longer than the other groups were

这就是一个比较典型的例子，than从句后可以补出为from Aleuts or Inuits of the North Pacific and northern Alaska——宾语, 也可补出为were Aleuts or Inuits of the North Pacific and northern Alaska——主语.两者意思大不相同。

相反，也有不会产生歧义，所以省略助动词的例子，一时找不到了，如果看到再贴上来。不知道对不对，请指正。