Our school life has become ________ than before because of all kinds of after-school activities.
colorful
colorfully
more colorful
the most colorful
What can we students do _____ the environment?
—How long have you lived in this town? —_____ 2001.
There are five people in the room, but I know _____.
Don’t give up _____ you will never succeed.
Trees can stop the sand _____ towards the rich farmland in the south.