GWD 17-32 现在完成时可以用在过去的时间？求大神指教

cician

GWD 17-32

Q32: [size=1em]Navigators have known for thousands of years that the ocean has variable currents, but it is only in the last half century that a reasonably clear picture has emerged of the patterns and causes of ocean currents. [size=1em] a reasonably clear picture has emerged of the patterns and causes of ocean currents a reasonably clear picture of the patterns of ocean currents and their causes have emerged a reasonably clear picture emerged of ocean currents, their patterns and the causes of them there have emerged a reasonably clear picture of the patterns of ocean currents and what caused them there had emerged a reasonably clear picture of the patterns of ocean currents and their causes [size=1em]   Answer: A

in the last half century ,看到这儿九把用现在完成时的ABD都排除了，楼主看到了前半个句子也用的现在完成时，但是没有时间限制所以应该没有问题吧？可是后半句有这个过去的时间段限制。楼主只好选了E，求牛牛解答。

ashlyzhu

within/during/over/in +the last/past recent +

ashlyzhu

within/during/over/in +the last/past recent +时间段用现在完成时。。。。

cician

ashlyzhu 发表于 2013-10-1 14:27
within/during/over/in +the last/past recent +时间段用现在完成时。。。。

不解，难道in the last ten years不是过去时间段？

ashlyzhu

cician 发表于 2013-10-1 14:30
不解，难道in the last ten years不是过去时间段？

最近的十年里。。。现在完成时：事情已经发生了，但是强调对现在的影响。。。

cician

ashlyzhu 发表于 2013-10-1 14:32
最近的十年里。。。现在完成时：事情已经发生了，但是强调对现在的影响。。。 ...

啊，这样呀／／就是有last和past的就要用现在完成时？那如果用过去时错么？

ashlyzhu

cician 发表于 2013-10-1 14:35
啊，这样呀／／就是有last和past的就要用现在完成时？那如果用过去时错么？ ...

看题目吧。。。。我在prep笔记上看到的。。。你可以下载来去看看。。。
反正像这种结构的都要用现在完成时：within/during/over/in +the last/past recent +时间段
或者碰到since的也要用现在完成时

cician

ashlyzhu 发表于 2013-10-1 14:38
看题目吧。。。。我在prep笔记上看到的。。。你可以下载来去看看。。。
反正像这种结构的都要用现在完成 ...

受教啦！谢谢！