(2014·北京海淀模拟)Only by improving education and high science technology can a country become a(n)________one.

Though Jane speaks Russian well, she thinks it necessary to learn ___ foreign language.

A clean environment can help the city bid for the Olympics, which ________ will promote its economic development.

 I just choose a simpler lifestyle，________ where I can ride my bike all over and do not have to make a great living to survive.

Nowadays there are still a number of students        school at various grades due to a lack of money in some poorer areas.