FOR
For主要跟在下面這些名詞的後面：
* a check for (amount of money)
例句: She gave me a check for $50.
她給了我一張50塊錢的支票。
* a demand for something
例句: Unfortunately, there wasnt enough demand for our product.
不幸的是，我們的'產品市場需求不大。
* a need for something
例句: There is a real need for discipline in this class.
這個班級，沒紀律不行。
* a reason for something
例句: I have a reason for doing that!
我這麼做是有理由的。
IN
In主要在下面這些名詞後面：
* a rise in something
例句: There has been a rise in prices recently.
最近價格上漲了。
* an increase in something
例句: We have seen many increases in production levels.
我們看到生產水平有了很大提高。
* a fall in something
例句: There has been a fall in prices recently.
最近價格有了下降。
* a decrease in something
例句: We have seen many decreases in production levels.
