In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores; by 1997 that figure had grown to nearly six hours a week.
语法 Sentence Correction-2507
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正确的用户笔记
chuster 2016-05-28 12:04:06
用分号连接，两个句子相对比较独立，而且出现了时间标志词by 1997,所以用过去完成时是可以的。 时间框架改变了，出现了by 1997,1981这个时间点就与后面的句子无关了 that figure这种用法也是可以的。 As for C, passive construction leads to grammatically inferior structure in the context. It seems slightly unclear who is doing the work. Passive construction is not really parallel in structure.
lauchiuyee 2015-08-19 17:04:38
【做错】chores后边是分号，A的they不能指代children；by1997用过去完成时
songzy3411 2015-04-02 20:55:40
that figure代指小时数已经grown
halowwww 2016-12-17 22:40:01
Ron: in this case, 1981 is actually, irritatingly enough, irrelevant. the only relevant places on the proverbial timeline are (a) when the number of hours started growing (this is the 'earlier event' or FIRST time marker), and (b) 1997 (the SECOND past time marker). because 1997 is in the past, and the 'arrow of relevance' points to / stops at 1997, you use the past perfect. if we were talking about a modern statistic instead ("as of today, the number has grown to..."), then we'd use the present perfect. -- here's a similar sentence: at the start of the 1991 track season, the world record in the men's long jump had stood for 23 years. same deal here. the start of the '91 season is the second time marker, the first being the time at which the record was set. (the 'arrow of relevance' on the timeline would be 23 years long, pointing to 1991, so the past perfect is appropriate again.)
jackshanhang 2016-11-22 11:11:18
时态就管自己的句子就好了
jackshanhang 2016-11-22 11:06:45
in this case, 1981 is actually, irritatingly enough, irrelevant. the only relevant places on the proverbial timeline are (a) when the number of hours started growing (this is the 'earlier event' or FIRST time marker), and (b) 1997 (the SECOND past time marker). because 1997 is in the past, and the 'arrow of relevance' points to / stops at 1997, you use the past perfect. if we were talking about a modern statistic instead ("as of today, the number has grown to..."), then we'd use the present perfect. -- here's a similar sentence: at the start of the 1991 track season, the world record in the men's long jump had stood for 23 years. same deal here. the start of the '91 season is the second time marker, the first being the time at which the record was set. (the 'arrow of relevance' on the timeline would be 23 years long, pointing to 1991, so the past perfect is appropriate again.)
糯米团子QUQ 2016-11-03 15:15:20
in this case, 1981 is actually, irritatingly enough, irrelevant. the only relevant places on the proverbial timeline are (a) when the number of hours started growing (this is the 'earlier event' or FIRST time marker), and (b) 1997 (the SECOND past time marker). because 1997 is in the past, and the 'arrow of relevance' points to / stops at 1997, you use the past perfect. if we were talking about a modern statistic instead ("as of today, the numberhas grown to..."), then we'd use the present perfect. -- here's a similar sentence: at the start of the 1991 track season, the world record in the men's long jump had stood for 23 years. same deal here. the start of the '91 season is the second time marker, the first being the time at which the record was set. (the 'arrow of relevance' on the timeline would be 23 years long, pointing to 1991, so the past perfect is appropriate again.)
Hellosaaama 2016-10-27 16:55:59
完成时 强调figure的对比
要考满分的晚琳儿 2016-10-23 16:21:30
1、分号相当于句号，后面是独立又完整的句子。又因为出现by 1997,所以用完成时。
桐桐不要大胖脸 2016-10-09 21:22:34
that figure指代前文出现过的2.5小时 by+过去的时间-->应该使用过去完成时，没有问题
Lottieeee 2016-10-07 01:52:23
一開始得1981跟後面那句無關，後面那句的重點是by 1997 直到1997年，所以用過去完成式 in this case, 1981 is actually, irritatingly enough, irrelevant. the only relevant places on the proverbial timeline are (a) when the number of hours started growing (this is the 'earlier event' or FIRST time marker), and (b) 1997 (the SECOND past time marker). because 1997 is in the past, and the 'arrow of relevance' points to / stops at 1997, you use the past perfect. if we were talking about a modern statistic instead ("as of today, the number has grown to..."), then we'd use the present perfect. -- here's a similar sentence: at the start of the 1991 track season, the world record in the men's long jump had stood for 23 years. same deal here. the start of the '91 season is the second time marker, the first being the time at which the record was set. (the 'arrow of relevance' on the timeline would be 23 years long, pointing to 1991, so the past perfect is appropriate again.)
sasazz 2016-09-27 10:27:46
by 1997是指“截止到1997这一年的时候”（不同“in 1997”），也就是说，到1997年的时候，这个figure已经达到6 hours a week，grow发生在1997前面，并且可能继续发生，所以用过去完成时还是比较合适的。
shisu0610041 2016-09-11 18:33:18
道题里by 1997是指“截止到1997这一年的时候”（不同“in 1997”），也就是说，到1997年的时候，这个figure已经达到6 hours a week,说明这个是发生在1997之前并且可能继续发生的，所以用过去完成时还是比较合适的。
