Ellen was a painter of birds and of nature，________，for some reason，had withdrawn from all human society.(2012·浙江，17)

The flood started and we had to_____higher ground.

It was not until dark _____ he found _____ he thought was the correct way to solve the problem. [ ]

The United Nations are evaluating the damage caused in Haiti earthquake, while in Chile the government itself ______ the lead role

I have $20 000 and I need $25 000,but my parents have promised to _______ the difference.