+) Thì QKĐ diễn tả hành động xảy ra và đã kết thúc trong quá khứ.
+) Thì QKTD diễn tả hành động đang xảy ra tại một thời điểm cụ thể trong quá khứ.
+) Nếu có hai hành động xảy ra trong quá khứ: HĐ đang xảy ra chia QKTD, HĐ khác xen vào (chia QKĐ).
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`4.` was waiting - arrived
`5.` was reading - heard - were playing
`6.` was still burning - arrived
`7.` was looking - came
`8.` heard - turned - saw - was
`9.` was wearing - saw
`10.` started - was - came
`11.` broke - was picking - cut
`12.` realized - were driving
`13.` was
`14.` met - was doing
`15.` were playing - decided
@ `Ly`