How often do you exercise?
你多久锻炼一次?
(1)“how often”是对表示频度的时间状语的提问，可翻译为“多久(一次)”。例如：
How often do you watch TV?
你多久看一次电视?
【拓展】与how有关的短语：how far(距离)多远;how long(时间)多长;how many多少(只可接可数名词的复数形式);how much多少(只可接不可数名词);how soon(时间)多久后(事情还要过多久才发生);how old(年龄)多大。
(2)exercise做动词时，可作及物动词，也可作不及物动词。例如：
She exercises two or three times a week.
她一周锻炼两三次。
She exercises the dog every day.
每天她都遛狗。
【拓展】exercise作名词时，意为“锻炼;运动”时是不可数名词，意为“体操;练习”时是可数名词。例如：
I should eat less food and take more exercise.
我应该少吃饭，多锻炼。
We do morning exercise every morning.
我们每天早上都晨练。
小练习
1. She often goes to the movies twice a week.(对划线部分提问)
________ ________ ________she ________ to the movies?
2. —______ is Lucky 52 shown on CCTV-2?
—Every week.
A. How long
B. How often
C. How soon
D. How many times
3. There are 35 boys in our class. (对划线部分提问)
________ ________ boys are there in your class?
4. ________ (exercise) helps us keep healthy.(用所给词的正确形式填空)
5. We do ________ ________(眼保健操) every day.