The rapidly growing birth rate brings about a lot of environment problems, which the government is supposed to take _____.

Those poor and needy teenagers were excited to find a shop at the corner where they could buy ____ priced bikes.

(2013·福建，31)Those poor and needy teenagers were excited to find a shop at the corner where they could buy ________ priced bikes.

As he works in a remote area, he visits his parents only _________.

It is commonly assumed that the growth of GDP and the development of people’s living conditions are not _______cause and effect.