如图为人体血液循环中某物质含量的变化情况.如果I代表肺泡外的毛细血管,Ⅲ代表组织细胞外的毛细血管,则此物质最可能是( )
A:氧气
B:二氧化碳
C:葡萄糖
D:尿素
关于声现象,下列说法中正确的是( )
_______the exam, we'll say good-bye to our dear teachers, classmates as well as ourbeautiful school.
water,the fish can not live.