—What did you _____ in Beijing? （  ）
—I visited the Great Wall.

A．do

B．did

C．doing

D．to do

-What can it________?(    )
-It can________.

A．do; swim

B．does; swimming

C．doing; swimming

They will ________ some red apples.  (   )

A．pick

B．picks

C．to pick

Read and correct the wrong words:
He didn’t walked to work yesterday.   ________________

用括号里单词的适当形式填空
1. When I am ________ (do) my homework, my mother is ________ (cook).
2. He has to _________ (travel) the country in search of work.
3. How __________ (do) seeds travel?
Seeds _________ (travel) in many ways.
4. What _____ (be) they talking about?
They are _________ (talk) about the seeds of plants.