Why are the housing prices in big cities going up all the time?——One reason is that people are__________ into overcrowded cities in great numbers.

________ will win the first place in the relayrace— I don’t know.

Are your parents doctors, too——No, they are teachers. ___ of them loveteaching very much.

Miss Wei often helps us ________ our English.

There are fewer and fewer tigers in India. The situation will continue ______ humans stop hunting them for their fur and bones.