PS:请写出为什么

题目

PS:请写出为什么
1.The old scientist has made ___ in growing rice,which will ___ more people in the world.
A.a breakthrough;feed on
B.a breakthrough;feed
C.a breakthrough;feed to
D.breakthrough;feed with
2.Is your house ___ now?
-Yes,it ___ a half month.
A.painting;takes B.being painted;will take
C.painted;will take D.being painted;takes
3.He made it ____ combining many others' methods.
A.with B.by C.for D.from

答案

看了之前两个人的答案,我无言以对.我的答案保证对!
第一题选B
第一空breakthrough是可数名词,要加冠词a,第二个空,句意需要说大米“养活”的更多人.feed on 以…为食,以…为能源；feed to向…提供食物 ,而feed有“供养,养活(家庭或群体)”的意思,所以选B
第二题选B
可以把题干还原成陈述句,my house is _____ now.很明显这里房子是正在被粉刷,所以选择being painted 现在进行时+被动语态.刷房子要花1个月,将来时,will take
第三题选B
他用将其他方式联合在一起的方式来做成了这件事.
后面的combining many others' methods是方式状语,所以应该用介词by引出来.