[[배택 청담동물미역#3136]] 급해서 도움을 청합니다!!!!

잡담 죄송합니다. 영어문법 아시는분 좀 알려주세요

답이랑 간단하게 틀린건 왜 들어가면 안되는지 알려주세요..

i ____ very angry yesterday, so i didn't talk to him.

1.am 2. had been 3. have been 4. was 

yesterday, i met a friend, saw a movie, and ____ home late.

1.coming 2. have come 3. came 4.had come

there used to be tem students ____ my class.

1.at 2. on 3. to 4. in

the traffic is very heavy, but i think, we'll get there ____ six o'clock.

1.before 2.on 3 ago 4. in

the robbers ____ the money when the police arrived.

1.count 2. counting 3. are counting 4.were counting