我每四个星期回家一次。
I go to library every fourth week.
我每隔三周去图书馆一次。
If you runhigh mileage (more than 30 miles a week), cut back your mileage by atleast 50% every fourth week.
如果你跑长距离的（每周超过30哩），每隔四周至少减少50%里程。
For example, he has owned a train and railway set since his fourth birthday, and he played with it almost every week until he was about seven.
例如，他从四岁生日起就拥有了一套火车和铁路玩具，他几乎每周都玩，直到七岁左右。
Take a week off every third or fourth week, or go long every fortnight instead.
每三或四个星期进行一次或者双周进行一次长途就足够了。
Fourth, write an English composition every week and ask teacher to revise that for me to improve the writing level.
第四，每周写一篇英语作文，请老师修改以提高写作水平。
Fourth, write an English composition every week and ask teacher to revise that for me to improve the writing level.
第四、每周写一篇篇英语作文，并让老师修改，以此来提高英语写作水平。
Fourth, write an English composition every week and ask teacher to revise that for me to improve the writing level.
第四、每周写一篇篇英语作文，并让老师修改，以此来提高英语写作水平。
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