So difficult did I find ___ to work out the problem that I decided to ask my partner for help.
The vegetables grown in this district are much better than ____ in that district.
_______ no buses , we have to walk home
It is ________ the customers' needs that has made chain stores so popular in big cities in China.
--- What ______ when I phoned you? --- I ______ my work, and I wanted to go out.
---I have _______that he will continue to rise to the challenges ahead. ---Absolutely.