What has encourage forest growth historically?
A. The government’s advocacy.
B. The use of wood for fuel.
C. The favorable climate.
D. The green movement.
查看答案
What account for our increasing desire for forest?
A. Their unique scenic beauty.
B. Their use as fruit plantation.
C. Their capability of improving air quality.
D. Their stable supply of building materials.
What does the author conclude about the prospects of forestation?
A. Deserts in sub-Saharan Africa will diminish gradually.
B. It will play a more and more important role in people’s lives.
C. Forest destruction in the developing world will quickly slow down.
Developed and developing countries are moving in opposite direction.
力法的基本未知量是
A. 多余约束力
B. 支座反力
C. 角位移
D. 线位移
去掉联结三刚片的复铰，相当于撤除几个约束
A. 2
B. 3
C. 4
D. 5
微信支付 
支付宝支付