Last Sunday, we visited the factory _____ my father ever worked for four years.

So far the teachers have _____ several solutions to the problem that some students often fail to hand in their homework on time.

The police chief advised his men to keep________ and not lose their tempers.

Having a walk after supper is certainly good for the old people, but it remains ______ whetherthey will enjoy it.[ ]

You drive on theright of the road in China. It’s the traffic rule.