Must или had to?

l forgot to phone Sam yesterday. I _ phone him today
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I forgot to phone Sam yesterday. I MUST phone him today.

had to используется в времени, а так как у нас указано настоящее [today], то тут подходит только must.

1. were shown

2. are developed

3. is being discussed

4. is being built

5. are devoted

6. is known

7. are being prepared

8. were done

9. was being cooked

10. are being sold 

ответ: 1-a) we  should not  burn  garbage.  it.            2- c) plants  growing  in the sea            3-c) greenpeace  protect  the oceans,  rivers, seas  and lakes            4-c)  we can  help the animals  if  we do not  cut wood            5-a)  we can help  the fish  if we do not  pollute the  oceans, rivers  and lakes