---We can use QQ to talk with each other on the Internet.---Really? But can you tell me _______it.
---He never says a bad word about anyone , ____? ---_____. He is very kind .
One of my ____ is clean, but _____ one isn’t .
When he walks ____ my desk , he often knocks my books ____ the floor.
The teachers often make us _____ in class , and life here makes us _______.
Light goes faster than sound.