By the end of 2011, all of China’s public art galleries(画廊)________free to enter.

Must I hand in our homework today?— No, you ______.

What ______ the forest of Yangzhou in the last 30 years?—Yangzhou has become much greener.

Mum ________ clothes, so I have to look after my younger sister.

Excuse me, I want to buy some stamps. Where can I find a post office? — I know ______ not far from here. You can find ______ without difficulty.