Tom was a black slave and he at last ______ the cotton farm to join the North Army.

＿＿ you know, I am with my aunt and grandmother

They don’t think the Internet will ________newspapers and TVs which have their own advantages.

－What do you think of the pollution－______ it’s serious, everyone can do something to save the world.

Air pollution has become__________ than ever before. We must do something to stop it.