Summit 1 - Unit 9

My books aren’t on the table where I always leave them. They _____ been taken by my husband.”

• had

• had not

• may have

• must

“Dinosaurs didn’t necessarily die off gradually from climate change; they _____ been killed off quickly by some sudden event. I guess”

a. could have

b. couldn’t have

c. had

• could have

• had

• couldn't have

• should

I don’t believe in any of the other theories. There is no doubt: Giza _____ been built by the ancient Egyptians

• could

• might not have

• might have

• had to have

Some of the visitors brought only long pants and sweaters; they _____ been told that it’s so hot and humid here

• must have

• could have

• must not have

• should

His story is really _____. I doubt that those things could have really happened.

• unsolvable

• questionable

• probable

• provable

I think she's telling the truth. Her description of the events very ____ to me.

• questionable

• believable

• solvable

• unprobable

The question of whether or not solar power is the answer to the energy crisis is _____. Experts offer many other solutions as well.

• debatable

• believable

• provable

• unsolvable

There are several theories about the mystery of the MH370, but with so little evidence, none are _____

• believable

• debatable

• provable

• believable

Peter thinks the John was lying about the value of that suitcase, but I actually think what he said is _____.

• solvable

• questionable

• believable

• debatable

The mystery of what happened to the famous US pilot Amelia is most likely ____ since her body and the plane have never been found.

• believable

• provable

• debatable

• unsolvable