Sam ________ some knowledge of the computer just by watching others working on it.

Why do you like going to Kunming for a holiday—Because the weather there is _____too hot ______ too cold.

.—Do you like working as a waiter? —–Yes, but I get tired ___ the whole day

When I go to school, I say “______” to my parents.

It is our duty to try to ______ production and reduce the number of things we make and buy.