21.Great changes ____ in the City of Guangzhou since 1980, and a lot of big buildings ____.A.were taken place, were set up B.have taken place, have set upC.have taken place, have been set up D.have been taken place, have been set up22.The pen ____quite smoothly.A.writes B.is writing C.can be written D.is written23.Water ____ into steam if it is heated to its boiling鄄point.A.is going to be turned B.will be turned C.has been turned D.is being turned24.—I saw that new film yesterday. —Did you? I ____ it ye...