21．Our team was ahead during the first half, but we _____ in the last ten minutes．
A．were won B．were lost C．were beaten D．won
22．Usually children are allowed to ___________ when they are six years old．
A．attend school B．attend the school C．join school D．join the school
23．Seeing their son playing computer games all day, the parents don’t know ______ it．
A．how to do B．what to do C．how to deal with D．how to do with
24．— So hard ______ in the past few months that he has made great progress in English．
— I can see that; only a few mistakes ______ in the exam．
A．has he worked; did he make B．he has worked; did he made
C．he has worked; he made D．has he worked; he made