语法书上讲到：
1.The farmer used wood to build a house which to store grains in.—该句错误
2.We moved to the country so that the kids would have a garden which they could play in.—该句正确
那种情况下介词可以置于句末？那种情况下不能？
“介词+疑问词+动词不定式短语”作后置定语时，不可以把介词移到动词不定式短语末尾。
The farmer used wood to build a house which to store grains in.（错误，which to store grains in不是定语从句）
The farmer used wood to build a house in which to store grains . （正确, in which to store grains是“介词+疑问词+动词不定式短语”）
The farmer used wood to build a house in which they store grains.（正确，in which they store grains是定语从句）
The farmer used wood to build a house which they store grains in.（正确， which they store grains in是定语从句）
