Berikan contoh simple past tense negatif,positif,introgatif

past tense:
+ The teacher came, i was a stamp collector
-  The teacher didn't come, i wasn't a stamp collector
? Did the teacher come?, was i a stamp collector?

(+) We bought a lot of snacks yesterday
(-) We did not buy a lot of snacks yesterday
(?) Did we buy a lot of snacks yesterday?