The Mississippi riverboat, which (evolved) from simpler (steamship) of the early 1800’s , became the (dominant) form of (passenger transport) on the Mississippi river. 作者: redpassion 时间: 2003-8-18 10:50
steamship错了，复数 所有以单数形式出现的单词一点要有东西“点缀“ 没有就一定错作者: wyxgeorge 时间: 2003-8-18 11:00
i strongly agree作者: Jone 时间: 2003-8-18 19:32
我明白了，谢谢redpassion和wyxgeorge。