On April 12, 1961,_____27—year—old Yuri Gagarin(尤里.加加林)became the first human to go into_____ space.
Nowadays scientists are working hard to find out ______ to do with air pollution.
Good teachers can usually give the students______ advice on their study.
Chinese people have been using paper for over______ years.
Mother came into my study with a cup of milk in one of her hands, and an apple in ______.
______ amazing the Disney film Frozen is!