阅读理解。 Life is like throwing and catching four balls of life in the air．You call the balls work,family,friends and minds．You will soon understand that work is a  rubber ball．If  you  drop it,it will bounce back (弹回)．The other three balls are made of glass  and  easy to be bro- ken,so you must know how to protect them．But how? Don't shut love out of your family by saying it's hard to find．The quickest way to get love is to give it; the fastest way to lose love is to hold  it closely;  and  the  best way  to keep love is to give it wings． Don't  think  that  you  are not so good as others．It  is because we are different and each of us is special．Never mind if you fall behind others．It's never too late to learn．Knowledge is a weightless treasure which you always carry easily． Don't let you life pass through your fingers by living in the past or in the future．If you live well today, you live all the days of your life． Yesterday is history,tomorrow is hard to guess and today is gift．That's why we call it 'The Present'． 1．Which is not the name of a ball talked about in the passage? A．work B．health C．family D．mind 2．To give it wings means to______ A．hold it closely B．give love freedom C．get ready for love D．keep love out of your family 3．Why is knowledge a treasure you can always carry easily? A．Because it is heavy． B．Because you can't protect it． C．Because it's never too late to learn． D．Because it is treasure without weight． 4．From the fourth paragraph,we know that A．people must have plans for the future B．people woul d rather live in the past C．people who live well today will live well every day． D．people who live in the past or in the future will not have long life．