We won’t forget the financial crisis and the troubles _______ has caused to the people all over the world．

______ has already been pointed out, only by correcting mistakes, can you make progress.

The sick salesman was happy to stay at home because doing _____ was a thorough rest for him.

---It’s a lovely day, isn’t it? ---Yes. I love ___when the weather is warm and sunny in winter. Why not sit outside and have a chat?

Nine in ten high school students say there are significant differences in their attitude toward chatting on line, compared with _________ of their parents.