For the engine to work, the green button ____ be in the “on” position.[ ]

The fact is that your passport has been________.So you can’t use it.

(2013·高考重庆卷)It was with the help of the local guide________the mountain climber was rescued.

You look unhappy, what’s happening, my son? —I’m wondering how long it’ll be________ we come to China again

. —________ do you eat junk food— Never.