1 after he had done his homework , he watched TV last night => before................... 2 the children cleaned up the beach then had lunch => after .................... => before......................

`1` After he had done his homework, he watched TV last night.

`->` Before he watched TV last night, he had done his homework.

`2.` The children cleaned up the beach then had lunch.

`->` After the children had cleaned up the beach, they had lunch

`->` Before the children had lunch, they had cleaned up the beach.

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`-` Thì quá khứ hoàn thành diễn tả một hành động diễn ra trước một hành động khác trong quá khứ

`-` Trong thì quá khứ hoàn thành:

`+` Hành động xảy trước chia ở thì quá khứ hoàn thành

`+` Hành động xảy ra sau chia ở thì quá khứ đơn

`-` Dấu hiệu: $before,$ $after,$ $by$ $the$ $time,...$

`-` Công thức:

$(+) S + had + V3 +...$