Definition: used to refer to a particular person or thing without naming or describing them Level: B1
博物馆只在一天的某些时间开放。
The museum is only open at ___certain times of the day.
在测验中，参赛者必须在某个时间内完成。
In the quiz, competitors must finish within a ___certain time.
她只从某些商店购买食物。
She only buys food from ___certain shops.
