1 was walking
→ thì QKTD : s + was / were + V-ing
2 was reading
→ thì QKTD : s + was / were + V-ing
→ dấu hiêu nhận bt : at this time last year
3 is - running
→ thì HTTD : S + be + V-ing
4 is eating
→ thì HTTD : S + be + V-ing
→ dấu hiệu nhận bt : now
5 am trying
→ thì HTTD : S + be + V-ing
6 was
→ thì QKTD : s + was / were + V-ing
→ dấu hiêu nhận bt : when
7 was riding
→ thì QKTD : s + was / were + V-ing
→ dấu hiêu nhận bt : while
8 were having
→ thì QKTD : s + was / were + V-ing
→ dấu hiêu nhận bt : when
9 is buying
→ thì HTTD ; S + be + V-ing
10 isn't studying
→ thì HTTD ; S + be + V-ing