星期 (xīng qī): 週；曜日；日曜日；曜日（数字との複合語で使用）；日曜日（単独または星期日/星期天で使用）

I am very busy this week.

There are seven days in a week.

I am going to Beijing next week.

What day of the week are you free?

Last week we went to the park.

What day of the week is it today?

On Monday I have to go to work.

Last week he was very busy.

I stayed in Beijing for one week.

On Saturday we are going to see a movie.