already多用于肯定句中,ever,yet,never多用于疑问句和否定句中.如：
I have already finished my homework．我已经做完家庭作业了.
Have you ever sung this English song?你曾唱过这首英文歌吗?
They haven't started yet．他们还没有动身.
We have never heard of it．我们从来没有听说过这件事.）
have(has) been to意为“曾经去过某地”,表示现在已经不在那里了.可与just,ever,never等连用.如：
I've just been to the post office.我刚才去邮局了.
Have you ever been to Hangzhou?你曾经去过杭州吗?
Mary has never been to the Great Wall.玛丽从未去过长城.