Do you know where Mary is— She has gone away ____ the weekend

Three problems are too hardto . Will you give me some advice? —-There are many ways. Themostt important is to have a careful plan.

It is said that the software on learning subjects for pupils in a very practical way

I won’t believe that five-year-old boy can read five thousand words_____I have tested him myself.

There has been thick haze(雾霾)in Zhijiang recently.—We must drive our cars less because cars people drive, _____ pollution there will be.