By the year of 2053 there will be 487 million aged people in China, means that one third of the population will be over 60.
Mother insisted that the child's hands ______ before dinner.
Plants grow well ______ there is plenty of water and sunshine.
—Did you write to Grace last summer? —No, but I'll ______ her over Christmas vacation.
In summer people usually stay up late outside, ______ the cool air.
The foreiger knows little about ______ is called "Hope Project" in China.