The college entrance examination(the gaokao)is one of the most important exams.Families take it_____.

Li Ming used________ on the right in China, but he soon got used ________ on the left in England.

It is the bus driver who should ______ the safety ofthe passengers.

Our Chinese teacher encouraged us _______ up even if we made a serious mistake in our writing work.

You promised your friend a letter; youought to ______ days ago