Ma Yun, head of Alibaba, is one of ________ persons in the world. — Yes. He is now even ______ than Li Jiacheng.

Let’s climb the mountain.—I don’t agree. _______ the mountain will make us exhausted.

Thoughthe series of books isabittoodear(昂贵),itisworthwhile_____________.

The rubbish _____ is produced every day is becoming a serious problem in cities around the world.

Tom, please tell me.—In the Olympic Sports Center.