一、often
adv.经常;常常;时常;再三
例句
1、This resulted in overpriced and often inferior products
这就导致了标价过高而往往质量低劣的产品的出现。
2、People often have incorrect information about food.
人们对食物经常会有不正确的'认识。
3、She was often downright rude to him.
她常对他十分粗鲁。
二、usually
adv.通常，经常，平常，惯常地;一直，向来;
例句
1、This year hotels that usually are jammed had vacancies all summer.
今年，那些通常爆满的旅店整个夏天都有空客房。
2、Finance is usually the biggest problem for students.
经济问题通常是学生最大的问题。
3、This condition usually clears up with regular shampooing.
这种情形通常多用香波洗洗头即可消除。