Mark was a student at this university from 2006 to 2011，________he studied very hard and was made Chairman of the Students’ Union.

I something wrong, or else Mom wouldn’t be so angry.[ ]

Now the transportation is convenient.It’s only____ ride from here to Beijing.

Nowedays, there is a____ increase in children’s creativity,for they are greatly encouraged to develop their talents.

Space exploration began in the 1960s, and since then about five hundred peopleinto space