It seems likely that a number of astronomical phenomena, such as the formation of planetary nebulas, may be caused by the interaction where two stars orbit each other at close range. (A) may be caused by the interaction where two stars orbit each other (B) may be caused by the interaction between two stars that each orbit the other (C) are because of the interaction between two stars that orbit each other (D) are caused by the interaction of two stars where each is orbiting the other (E) are caused by the interaction of two stars orbiting each other 请问b选项这里two stars that each orbit the other，这个each后边的orbit不用单数形式是因为orbit真正的主语是stars吗，那each在这里是做什么成分呢

It seems likely that a number of astronomical phenomena, such as the formation of planetary nebulas, may be caused by the interaction where two stars orbit each other at close range. (A) may be caused by the interaction where two stars orbit each other (B) may be caused by the interaction between two stars that each orbit the other (C) are because of the interaction between two stars that orbit each other (D) are caused by the interaction of two stars where each is orbiting the other (E) are caused by the interaction of two stars orbiting each other 请问b选项这里two stars that each orbit the other，这个each后边的orbit不用单数形式是因为orbit真正的主语是stars吗，那each在这里是做什么成分呢

老师您好，这一类题我错的比较多，因为一直不清楚前后比较的对象是什么。像这道题比较的是aspirin prevents和common drug prevents，但我却想成了aspirin和common drug比较。 在其他一些题里，选线中会有类似“...more than that of A”和“more than A” 我不知道比较对象是什么，所以很难排除选项。不知道这种题有什么解决办法。谢谢。

之前有道题听徐诚老师说过，比较题里经常把do,does提到前面来说。所以做到这题就选了B。请问什么情况下该提前，什么情况不能提前呢？

According to a study published in The New England Journal of Medicine, aspirin prevents blood clots just as well as a commonly used and more expensive blood-thinning drug does. prevents blood clots just as well as a commonly used and more expensive blood-thinning drug does prevents blood clots just as well as does a commonly used and a more expensive blood-thinning drug prevents blood clots just as well as will a commonly used and more expensive blood-thinning drug works just as well as a commonly used and more expensive blood-thinning drug at the prevention of blood clots works just as well as does a commonly used blood-thinning drug, which is also more expensive, at preventing blood clots