When it______ air pollution, Beijing faces the three “C” s-----cars,coal and construction,which lead to Beijing's thick air pollution.
— We’ll go to climb the moutain this weekend. Would you like to join us?— _____
He was born in Beijing and _____ by his grandma in a seaside village.
People _____ much more by their gestures than by their words.
Whoever leaves the lab last, _____ all the lights are turned off.
Nobody can tell _____ the future world will look like.