.—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.
I often have conversations with John over ______ telephone, whileI keep in touch with Tom by ______ letter.
Time is limited and let's come______ to the point.
Can you imagine the trouble that they had ___ the orphan in the terrible years?
It is the second time that I____ in Beijing
the deadline approaching, we found ourselves a loss about what to do.