误区一： that 与what 的混用
1. That they are going to discuss at the meeting is how to increase food supply in the world.(错误)
What they are going to discuss at the meeting is how to increase food supply in the world. (正确)
注：that在引导名词性从句时本身没有意义，也不在从句中充当任何成分；而what则表示“什么”“……的东西或事情”，在从句中充当主语，宾语或表语等。上句中的what 应充当discuss的宾语。
