–It’s hard for me to go to sleep.–Try to ____ the amount of coffee you drink during the day.

Scientists are convinced _____the positive effect of laughter _____physical and mental health．

I saw a strange cloud ___________ questions__________ it in the game.

Scientists and doctors across the world have done _____ research over the years, hoping to find a cure for cancer.

This morning Tom got up ealier ___ be late for school.