The police have started an ___ into the cause of the fire which broke out in the hotel last night.

Many scientists have believed that there may be a _________of life on the Mar．

Mr. Barren doesn’t think that all bad language should be allowed. In his opinion, there are ___________ that should be kept up.

The company turned a deaf ear to the workers’ _____ about their pay and working conditions.

.The businessman asked a much ______ price than ______.