In fact fuels we burn and plant food we eat ______ their chemical energy in the form of heat.
23.Nothing taught by others can have the same effect on you as learned by yourself.
Jack must be helping his grandma to water the flowers,______?
— Why are the four students so happy? —______ in the science competition, they are awarded prize money totaling $ 20,000.
The weather turned out to be fine yesterday.You __the trouble to carry your raincoat with you.
The little boy who got lost decided to remain _____ he was and waited for his dad.