as a conjunction
expressing a result
eg:
she was so tired that she couldn't think.
expressing a reason or cause
eg:
he seemed pleased that I wanted to continue.
introducing a subordinate clause expressing a statement or hypothesis
eg:
she said that she was satisfied.
我觉得句意应该是想学好英语只掌握一些语法知识是不足够的,还需要常常练习