Complete the second sentence so that it has the same meaning as the first one.

`80.` He was not at school yesterday because he had a headache.

`-` not go to school `=` not at school: không đi đến trường `=` không ở trường

`->` because `+` mệnh đề nguyên nhân

`->` thì QKĐ:

`(+)` S + Ved/V2

`(-)` S + was/were + not + adj/N