237. 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

Choice C can be faulted because to form a passive construction, are should take a verb form such as caused rather than an adverb such as because. Also, the phrase two stars that orbit each other illogically suggests that there are two particular stars causing all the phenomena in question, rather than various sets of stars in various loca­tions. （og裡說那個that變成限定！所以不好）所以我認定E選的orbiting是非限定！　　但ETS的官方回復說：In question 237 in the 10th edition, the use of the phrase "are because of" is what ultimately makes choice C incorrect, as described in the explanation. The distinction between choice C and the correct choice, E, is not a distinction between types of modifiers, however; both C and E contain restrictive modifiers　　這是怎麼一回事？如果E也是限定那為什麼對？　ETS不是在自打嘴巴了嗎？？？