確保一句中有且僅有一個謂語動詞
錯例：It is unclear recycling can control pollution.
正解：It is unclear whether recycling can control pollution.
改錯練習：
1. It is advertising makes us buy something impulsively.
2. There are two line charts show the unemployment rate fluctuates in China.
3. The percentage of families have one car increased greatly.
錯例：It is unclear recycling can control pollution.
正解：It is unclear whether recycling can control pollution.
改錯練習：
1. It is advertising makes us buy something impulsively.
2. There are two line charts show the unemployment rate fluctuates in China.
3. The percentage of families have one car increased greatly.