With more and more farmers moving to cities, an inadequate labor force is    becoming a major factor affecting the country's grain output.

（2014年安徽省合肥市高三第三次教学质量检测）23. -- Don't you think Carl was brave to go wingsuit flying?-- Personally, I think he was ______. He shouldn’t have risked his life to do so.

I can’t spend___ money on the car which is ___expensive for me .

As a student in Senior Three, I must work hard．______, I should take exercise to strengthen my body．

There was a long queue for coffee. Having waited for 10 minutes, we _______ gave up.