如图中“大白”和“小黑”的对话反映的主要问题时( )
A:过度捕捞
B:水土流失
C:气候变暖
D:土地沙化
—May I help you?You seem to be having some problems.
—________,thanks. I think I can manage.
如图,刻度尺的分度值是____,木块的长度为____cm.