Buying the house seemed to be a great idea at that time，but now I can see it was a terrible .

. I think immediate action should be ____toprevent the facories sending out waster

He ______ at once when I promised to help him.

_____ is estimated is that 300 million farmers will become urban dwellers in three decades.

So hard-working _____ that he sets agood example to all the other classmates.