Answer:
1.There has been a snowstorm in the mountains. The roads might not be passable.
2.We should call Tim before going to his house; he might not be there.
3.Unfortunately, James and Michelle have already made plans, so they couldn't come with us to the exhibition at the Museum of Contemporary Art.
4.Eve wants to go to the ballet, but she might not be able to get time off that evening.
5.The video is gone. Doug must have taken it.
6.Susan couldn´t hear the speaker because the crowd was cheering so loudly.
7. Jerry couldn't be angry at me. I've never done anything to upset him.
Step-by-step explanation:
"Can/Could" and "May/Might/Must" are Auxiliary Verbs. "Could" is the past form of the verb "can" and is used to describe an ability from the past and to express something that is a possibility. "Might" is the past form of "may" and is used to express something possible in the present. "Must" is used to describe something necessary or very likely.