good manners to say “Sorry” when you knock into someone but no need to say it again and again .
A yellow background will make the black characters___
Catherine’s mother doesn’t ___of her meeting her online friends in case she meets some bad guys
The new policy that people over 65 can take buses free of charge will___the elders a lot
Hardly could he___this amount of work in such a short time
Those who have___floods and sandstorms know the importance of environment protection