Before the managers started using word processors and graphic representation tools, advertisements were designed by in house calligraphers. 这个句子如果变成 Before the managers started using word processors and graphic representation tools, advertisements had been designed by in house calligraphers. 的话，是错了，还是只是有效性问题。谢谢哈~~ -- by 会员 qinqin2012 (2012/10/6 19:11:14)
umm
大致上应该是有效性问题，这个章节manhattan有讲的
可以给你贴一个：
Note that we do not always use the Past Perfect for earlier actions. In general, you shoulduse Past
Perfect only to clarify or emphasize a sequence of past events. The earlierevent should somehow
have a bearing on the context of the later event. Moreover, if the sequence is already obvious,
we often donot need Past Perfect.
Right: Antonio DROVEto the store and BOUGHT some icecream.
We already know that drove happened before bought. A sequence of verbs with the same subject
does notrequire Past Perfect. Rather, use the Simple Past for all the verbs.
Right: Antonio DROVEto the store, and Cristina BOUGHTsome ice cream.
In the sentence above, which has two mainclauses linked by and, we are notemphasizing the
order of events (although drove probablyhappened before brought). Clauseslinked by and or but
do not requirethe Past Perfect as a general rule.
Right: Laura LOCKEDthe deadbolt before she LEFT for work.
Likewise, we already know that locked happens before left because of the word before. The word
before and after indicate the sequence of events clearly and emphatically enough to make the use
of the PastPerfect unnecessary.
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发表于 2012-10-6 16:30:49
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