21.It is common that there are generation gaps between parents and their children，for the values of today’s young people differ from of their parents.
A.ones B.one C.that D.those
22.I invited Joe and Linda as well as Tom to dinner，but of them came.
A.neither B.none C.either D.both
23.—Oh，no!This stupid compcoter has crashed again!
—Well，you can try ，since there are so many available.one
A.another B.other C.the other D.others
