always,usually,often,sometimes用法的区别?急!@

always
adv.
总是
Healways comes late
他总是迟到.
永远
I shall always remember myfirst day at school.
我将永远记住我上学的第一天.
usually
usual + -ly
[5ju:VJElI]
adv
通常,经常
often
oft“常常”的异体字
[5Rf(E)n; (?@) 5C:fn]
adv
多次； 时常
How often do you go there?
你多久去那里一次?
How often you have been abroad?No often, only twice.
你出国几次了?不多,只出去过两次.
经常；通常
Children often dislike homework.
孩子们通常都不喜欢家庭作业.
He often does this.'
它经常干这种事.'
sometimes
some某一+ time时间
[5sQmtaImz]
adv
有时,时不时地,间或
I sometimes think that it is a great mistake.
我有时想这是一个大错.
Sometimes I help my mother in the house.
有时候我帮助妈妈做家务.
Sometimes the 'classroom' is a Mississippi riverboat.
"有时候,教室就在密西西比河上的汽船上."
"Sometimes, when Billy is sick, his older brother has to deliver the newspapers."
"有时毕利病倒了,他的哥哥就得去送报纸."
程度的频繁到不频繁：
always 总是 -- usually 通常 -- often 经常 -- sometimes 有时 - never从不
用法：
放在be动词和助动词后面；行为动词前.
特殊用法：
1 sometimes可以放在句首、句中和句末
2 often 也可以放在句末