`-` Câu khẳng định ( thì QKTD): S+ was/ were+ Ving

`-` Câu khẳng định ( thì QKĐ): S+ Ved/ V2

`-` Thì QKTD diễn tả `2` hành động diễn ra song song nhau trong QK.

`-` Thì QKTD diễn tả `1` hành động đang xảy ra  thì bị `1` hành động khác chen vào tring QK. Hành động đang xảy ra chia QKTD, hành động chen vào chia QKĐ.

`-` Thì QKĐ diễn tả các hành động nối tiếp nhau trong QK.

`4`. was listening `-` was explaining

`5`. were doing `-` were lying

`6`. woke `-` looked

`7`. welcomed `-` asked 

`8`. broke `-` had

`9`. were swimming `-` were sunbathing 

`10`. came `-` looked `-` told

`11`. were preparing `-` were collecting 

`12`. wree having -` were running

`13`. turned -` went

`14`. was doing `-` broke

`15`. was playing `-` was doing

`16`. drank `-` ate

`17`. was having `-` heard

`18`. was working `-` passed

`19`. went `-` took `-` began 

`20`. started `-` wanted