7. Past tense
( +)
( - ) S + Didn’t + V1 + O
-I didn’t teach class yesterday
-My boy friend didn’t call me last night
-In the past, I didn’t like him, but now I
like him
8. Past tense
(?) Did + S + V1 + O
-Did you call me last night ? Yes, I did
no, I didn’t
- Did you meet him yesterday?