To keep healthy,Professor Johnson ________ cycling as a regular form of exercise after he retired.[ ]

______. Is there a post office in the neighborhood– It’s next to the big mall on Green Street.

Some people are good at ________ but bad at giving back.

The old man put his oars （船桨）in the water and _______ thesmooth surface of the lake.

_____ do they have in the desk — Some books.