247: even though is more preferrable than even if, and if-clause 不应该用将来时 253: just as用来连接两个比较从句 254: 有争议的一道题。相关讨论见下面链接 http://forum.chasedream.com/dispbbs.asp?boardid=23&star=1&replyid=577466&id=65727&skin=0&page=1 265: consider X + adjective 也是consider的固定用法之一。consider noun; consider noun + noun; consider noun + adjective; consider that; consider 266: fell by x percent中的by X最好紧跟在fell的后面。同理可类推到所有drop, decrese, increse, rise等动词