often, always, sometimes, usually
这四个词意思相近。它们的区别是：
1.表示的频率不同。例如：
He comes to school on Monday,Tuesday,Wednesday,Thursday,Friday,Saturday and even on Sunday.我们可说：He always goes to school.always表示的频率是100%。
He comes to school on Monday,Tuesday,Wednesday,Thursday and Friday.我们可说：He usually goes to school.usually表示的频率是90%。
He comes to school on Monday,Tuesday,Wednesday and Thursday.我们可说：He often goes to school.often表示的频率是60%。
He comes to school on Monday and Thursday.我们可以说He sometimes goes to school.sometimes表示的频率是20%。
2.always的反义词是never; often的反义词是seldom; usually的反义词是occasionally, sometimes的反义词是always。
often, frequently
这两个词都可表示“经常”。它们的区别是：
often是常用词,强调的是经常性,具体时间意味不强; frequently比较正式,强调在某一具体时间内某事一次接一次地发生。试比较：
He comes here very often.
他经常来这儿。
He comes here very frequently.
他来这儿很频繁。
always，often，usually，frequently，repeatedly，regularly
这些副词均表示频度。
always总是，永远。语气最强，指在一切时候，没有例外。
often经常，语气弱于always,侧重动作发生的次数具有经常性，具体时间意味不强。
usually通常，通例地，指习惯性动作，频度仅次于always，较often大，偶尔有间隔。
frequently时常，经常，与often同义，可通用，但较正式，强调次数频繁。
repeatedly屡次，强调次数多，但反复的频率不一定均匀。
regularly用于修饰经常而有规律性的动作。
