I can’t believe that there are _____ many poor people in ____ a rich country.

Up to now, Hope Project has helped thousands of students who would       have dropped out of school.

There was such a long queue for coffee at the interval that we ____ gave up.

A model or an experiment in a science class can help us see things which would       remain hidden．

You should know _______to spend all your money on those impractical fancy goods.