already | 常用于肯定句中 | 常位于助动词 have/has 之后，过去分词之前 |
yet | 一般用于否定句和疑问句中 | 常放在句末 |
I have already finished my homework.
我已经完成我的家庭作业了。
Has she gone to school yet? 她已经去学校了吗？
注意：在现在完成时的句子中，含有already的肯定句变为否定句或疑问句时，要把 already 变为 yet，并放于句末。
肯定句：He has already finished reading the book. 他已经读完这本书了。
否定句：He hasn't finished reading the book yet. 他还没有读完这本书。
一般疑问句：Has he finished reading the book yet? 他读完这本书了吗？
—Has your sister finished reading _____?
—Yes. She has _____ finished it.