always,often,usually 如何区别?

always
ad.
1.总是,经常
They always make fun of Mr.Smith.
他们总是嘲弄史密斯先生.
2.永远,一直
Children's Day is always the first of June.
儿童节一直是六月一日.
3.(动词用进行时)老是,一再
I'm always misplacing my glasses.
我老是将眼镜乱放而找不到.
4.(与can/could连用)随时
You can always resign if you feel unhappy.
如果你不满意,随时可以辞职.
often
ad.
1.常常,时常
We often go hunting.
我们常常去打猎.
He is often late for class.
他上课时常迟到.
2.往往,通常
Man is often taller than woman.
一般说来男子比女子高.
usually
ad.
1.通常地;惯常地