China ________ the agreement and there are now 31 Chinese sites ________ the World Heritage list.
—Lucy doesn't mind lending you her dictionary.—She________. I have borrowed one.
He________have completed his work; otherwise, he wouldn't be enjoying himself by the seaside.
He paid for a seat, when he________have entered free.
________such heavy pollution already, it may now be too late to clean up the river.
John, look at the time,________you play the piano at such a late hour?