Help to translate into English sentences

1. He doesn't need a lot of money and is happy to lead a simple (lead a. . . life). .life). He does not need too much money, and he is willing to lead a simple life.2. Four generations living together is a proud tradition custom in China.2. Four generations living together is a proud tradition custom in China.3. The teacher standing in front of the platform can know which student doesn't perform well without watching him.4. If we are sure to complete it on time, we must stick to the work... If we are sure to complete it on time, we will have to keep on working.5. I was about to leave the supermarket when I happened to see my old friend.