（题文）I am ________ a letter ________ my aunt. (　　)

A．writing; at

B．write; to

C．writing; to

请根据图片回答下面的问题：
What are you doing?

用词的适当形式填空。
【小题1】Asia has the ________(large) population.
【小题2】Africa is the _______ (hot) continent in the world.
【小题3】There was a little note. It _____ (say), “Thank you.”
【小题4】Santa Claus is_______ (finish) his travels around the world.
【小题5】There are all ______ (kind) of cakes in the restaurant.

She is ______ a shirt .

A．wear

B．wearing

C．wears

I am ________ my homework. (   )

A．did

B．doing

C．do