The chemistry teacher demanded that the laboratory report _________ immediately after the experiment was done.
Scientists are convinced ______ the positive effect of laughter ______ physical and mental health.
---I’m going out tonight.---Well, I’d rather you ______.
Bitten twice, the postman refused to ______ our letters unless we changed our dog.
______ to go abroad alone is what worries me most.
When I said someone was stupid, I didn’t ______ you.