`1.` for

`2.` since

`3.` for

`4.` since
`5.` for

`6.` since

`7.` since

`8.` for

`9.` for

`10.` since

`11.` since

`12.` for

`13.` for

`14.` since

`15`. for

`16.` since

`17.` for

`18.` for

`19.` since

`20.` for

`21.` For - have been

`22.` has become - since

`23.` have written - since

`24.` Have you seen - for

`25.` haven't seen - for 

`26.` have you waited - for

`27.` hasn't washed - for

`28.` haven't had - since

`29.` has practiced - since

`30.` hasn't had - since

- for+ khoảng thời gian: trong, trong khoảng → chỉ một hành động, sự việc diễn ra trong suốt một khoảng thời gian nào đó

Ex: for 2 years, for a week, for ages ...

- since+ mốc thời gian: từ, từ khi ... → chỉ một mốc thời gian mà hành động bắt đầu diễn ra

Ex: since 2021, since Tuesday, since 9 o'clock ...