31. The cheering went on for quite some time _____ it died down and people took their seats again.
Our government's plan to fight against air pollution will focus on ________ information and handling PM2.5.
In fact fuels we burn and plant food we eat ________ their chemical energy in the form of heat.
Don't be so discouraged.If you ________ such feelings, you will do better next time.
Schools in China are required to ________ at least one “Sports Day” per academic year.
Adopting the doctor's advice, he ________ coffee and cigarettes and ate a balanced diet.