It has been announced that candidates ( 候选人)_____remain in their seats until all the papers has been collected .

Everyone should help save the planet. — Yeah. I’ve stopped ______ plastic bags when shopping.

Do you know Tom very well —– Yes, he and I ______ friends since we met in Jiangyin in 2002.

As to the question of whether we will sell our house or who we shall sell the house to, you ____ have answer by tomorrow.

This accident (事故) happened (发生) ________ a winter afternoon.