The Human World (7)

1 Those trees on the mountain are often cut down because they can be used as good material for building and firewood.

2 The oil of lamp is worn out because it burns itself to illuminate other.

3 Cassia bark is both traditional medicine and the trimmings for dish so its branches and bark are always cut off.

4 The sap of varnish tree can be use to make lacquer so it is cut all the time.

5 We all know the use of thing but forget the subtle effects of uselessness.