A:封号和耕牛
B:土地和耕牛
C:土地和人口
D:人口和鉄犁
激光技术是在1960年发明的.激光被誉为神奇的光,关于激光的应用下列说法中正确的是( )
A survey was made about what to do if there was a fire. These are some of the replies.