The purpose of new technique is to make life easier,________it more difficult.
You can’t imagine what difficulty we had _________ home in the snowstorm.
. The _______ boy was last seen _______ near the East Lake.
Don’t leave the water_______ while you brush your teeth.
The salesman scolded the girl caught ______ and let her off.
11. Though I have often heard this song ______, I have never heard you ______ it.