The design ________ all the ages and socialgroups is not easy to make.

d a bad week. He lost his job,________ ,his car was stolen.

Your good friend should you when you are sad.

Leaders of many countries have been trying to _____ what it is that makes China develop so fast in recent years．

In our school, students are accordingto how much they know and how old they are. A．classified B．combined C．listed D．made