The author's attitude towards the current situation in the exploitation of natural resources is______

A．Our living space on the earth is getting smaller and smaller
B．Our living space should be measured in cubic volume
C．We need to take some measures to protect space
D．We must create better living conditions for both birds and animals

A．they had no idea about scientific forestry
B．they had little or no sense of environmental protection
C．they were not aware of the significance of nature study
D．they had no idea of how to make good use of raw materials