大全95， 这个...

1.        Although some officials noted that using machines for farming in China costs more than traditional hand cultivation, the mechanization of farming in the laceType>villagelaceType> of laceName>Long BowlaceName> doubled the corn yield while the previous year’s costs were cut in half.

(A) mechanization of farming in the laceType>villagelaceType> of laceName>Long BowlaceName> doubled the corn yield while the previous year’s costs were cut in half

(B) mechanization of farming in the laceType>villagelaceType> of Long Bow doubled the corn yield while cutting costs to half those of the previous year

(C) mechanization of farming in the village of Long Bow doubled the corn yield as cost were cut to half of the previous year’s

(D) farming mechanization in the village of Long Bow doubled the corn yield as it cut in half the previous year’s costs（B）

(E) farming mechanization in the village of Long Bow doubled the corn yield while costs were cut to half that of the previous year

while在这里是什么成份，什么意思？怎么后面直接跟分词呢？谢谢指点。

while带让步或时间状语从句，且从句的主语是主句主语，从今可简化为动词的ing形式。表让步，简化后，while不变。

时间状语从句变ing，while可不变也可以变成in。when是变成on/upon。所以当你看到时间状语是in doing很可能就是由while sb/sth do转化的，而upon/on doing就是when sb/sth do转化的，其中sb/sth就是主句主语。

kiwii，这种问题语法书上都有介绍，建议你多看看语法书，如果因为不了解这些基本语法知识而做错，有点冤。

请斑竹推荐一个能下载语法书的地方吧，我在北美，语法书买不到的说

超星是个不错的地方。想办法弄个超星的读书卡账号吧。

(B) mechanization of farming in the laceType>villagelaceType> of laceName>Long BowlaceName> doubled the corn yield while cutting costs to half those of the previous year

(C) mechanization of farming in the laceType>villagelaceType> of laceName>Long BowlaceName> doubled the corn yield as cost were cut to half of the previous year’s

我想问half 的用法，half of也是可以的，half 作为名词，half those，half 是作为adj吗？

如果c选项改为costs就对了，是吗？

也是同样问题。

1，half those里half是形容词？

2，仅half也可以，half是名词？