We went to Hainan Island on May Day and had great fun ________ in the sea.
Many old men prefer __________ in a peaceful countryside.
Mary likes learing English,______ she doesn’t like learning math at all.
------I’m taking the driving test next Sunday.------________!
______ trees are cut down in the forests every year.
The population of the world in 20 century became very much _____than that in 19 century.