1、关联词不能省略
2、从句用陈述语序
从句的名词后接同位语
fact, idea, word，promise, saying，problem, news
常见引导词
that, whether, where, how, etc.
The facts that he succeeded in the experiment pleased us.
An idea came to her that she might do that in another way.
Scientists have argued over the problem whether there is life on other planets.