118. Art museums do not usually think of their collections as capital or consider the interest income that would be generated if a portion of the capital would have been invested in another form.
(A) be generated if a portion of the capital would have been
(B) have been generated if a portion of the capital would have been
(C) be generated if a portion of the capital were
(D) be generated if a portion of the capital was
(E) be generated if a portion of the capital had been
答案是: C
問題1:a portion....不是單數嗎?為什麼是用were而不是用was
問題2:怎麼判斷if後面什麼時候要用過去式,完成式...我一直都搞不懂
請大家幫忙~