A:y=90ax+10x
B:y=25ax+5x
C:y=20ax+5x
D:y=10ax+10x
下列各项,属于保护生物圈的人类活动的是( )
____ ____ is a traditional Chinese skill.
图为我国地形图,读图回答下题。
一He needn't. I have borrowed one.