500: the likelihood可接of or that clause 503: 独立主格结构. The answer I chose doesn't have conjuctive to connect to independent clauses. 504: share和the same的同时使用 redundant 505: A tricky question. http://forum.chasedream.com/dispbbs.asp?boardid=23&id=49654&star=2#1729899 514: 眼花了,一个as much as的普通比较结构 517: 没理解句意. 518: Need "and" to connect the last item in the parallel structure.