1.He devotes most of his spare time to keeping company with lonely old people in the seniors' home.
2.Whoever has not experienced some failures is unlike to appreciate the joy of success.
3.Life is a journey,in which opportunities and challenges coexist.
4.Now that you are not interested in our discussion topics,I think there is no need to continue our discussion.
5.Only when you have lost something do we find it valuable.Therefore,learn to appreciate what you process now.
第二个可能有点不好