4．A．The population of Asia is over three billion.

       B．There are more people in Asia now.

        C．Asia has three billion people.

3．A．People can recycle some waste things.

        B．People need many new things every day.

       C．People are wasting things now.

2．A．countries              B．continents            C．contact

1．A．2009               B．2019              C．2090