A:①②
B:②③
C:③④
D:①③
下列选项中,属于动植物共有的糖类是
卤代烷烃曾用作冰箱制冷剂,但在高空中与某些气体发生反应,破坏臭氧层,而被逐渐淘汰.如氟氯甲烷(CF2Cl2)在高空中会发生如图所示的变化,根据图示,判断下列说法中不正确的是( )
People in Colombia needn't make plans to meet their friends. They often just drop by them.