Mr. Green is said _____ an experiment to prove the new method of solving the problem when young.
When did you------ English? When I was in college.
We’ll look into the case as soon as we can. Just be ________, please.
How the big forest fire has ________ remains to be a mystery.
Only ______ a human being.
---Why didn’t you tell me the truth about his illness? ---___________, I knew nothing about it at that time.