“As” 一词拼写简单，用法可不少！
1. 用 “as” 来比较两个人或事物。搭配 “as…as” 可以表示 “一样，不分伯仲”
My house is very small – hers is twice as big.
He is as tall as his brother.
2. 用 “as” 来描述人的职业或事物的功能。
He works as a nurse.
You can use coconut oil as cooking oil.
3. 用 “as” 描述两件事同时发生。
I was just thinking about you as you rang.
The doorbell rang as I was cooking.
4. 用 “as” 引出原因，类似于 “because”。
I didn't go to the party as I was tired.
I forgot to send the email as I was stressed.
