根据中文提示，用单词或短语的适当形式填空，完成句子。
无论我们遇到什么困难，我们都应该试着笑对人生。
No matter what trouble we have，we should always try to________________.
如果你想要成功，你得不断尝试，绝不放弃。
If you want to succeed，you should keep on trying and never _______________.
他的电脑比我的便宜得多。
His computer is                 mine.
直到现在，三聚氰胺仍然在一些食品中被发现，所以我们应该选定适合的方式来避免。
Up till now, Melamine has still been found in some food, so we must  _____________suitable ways to prevent it .
在你上交试卷之前，你最好再次仔细检查。
Before you hand in your examination papers, you had better ___________ again.