The hot-spot trails formed by volcanic island chains indicate the positions of tectonic plates as for back as the present ocean basins have existed.后半句 as for back as the present ocean basins have existed 是什么意思？
...句话Even if you didn't send a thank you, she'd give you another gift the next chance she had. 其中让我想不懂的是the next chance she had这部分是什么结构呢？一开始觉得是一个定从修饰the next chance，而the next chance本身充当状语，但...
After divided into three groups, all the students set off for thetop
of the mountain.问：此题是道改错题，答案是“在divided 前加being, 说after此处为介词，这我能懂。但为什么不能是状语。从句的省略: After (all the students were) divided into three
groups, all...
Restless, shifting, fugacious as time itself is a certain vast bulk of the population of the red brick district of the lower West Side.这是欧亨利的短篇小说The Furnished Room(带家具的出租屋)开头部分：我没看懂该句的结构，麻烦老师把句子分析一下成分以及如...
...看以下句子（摘自考研英语某篇文章）：It signals a change in what has, until now, been a key element of scientific endeavor.【参考译文】该报告（It回指上文提到的报告）还表明，科学事业一直以来的关键因素将会发生改变。【我的疑问】书上...
...英语是用一般过去时还是过去完成时。比如：I (had) meant to come, but something happened. 我本想来，但有事就没有来。 I (had) intended to speak, but time did not permit. 我本想发言，可是时间不允许。以上两句中的had可以省略吗？