1.The forests of the tropics produce a magnificent growth of trees,but commercial lumbering is inhibited by problems that increase the cost of removal.The proliferation of species that is common to all tropical forests creates difficulties because ma

1.The forests of the tropics produce a magnificent growth of trees,but commercial lumbering is inhibited by problems that increase the cost of removal.The proliferation of species that is common to all tropical forests creates difficulties because ma
1.The forests of the tropics produce a magnificent growth of trees,but commercial lumbering is inhibited by problems that increase the cost of removal.The proliferation of species that is common to all tropical forests creates difficulties because many species are worthless.The lumberman combs the forest,therefore,removing the valuable trees that are convenient to waterways,and floating them downstream to a sawmill.Unfortunately,tropical hardwoods tend to grow slowly; an area once cleared needs substantial time to recover,forcing the sawmills to become mobile.Distance to market tends to be considerable,raising costs of transport.Because of these difficulties,only the most valuable woods can absorb the high costs associated with production.Other trees are left untouched.
1).According to the passage,one of the problems of commercial lumbering is ____.
A.selecting valuable trees is difficult
B.there is little variety in the types of trees in the forests
C.many of the trees are useless for timber
D.very few hardwoods grow in the forests
2).The lumbermen search the forests for valuable trees and choose the ones that ____.
A.are tropical species
B.are easy to cut down
C.are near to rivers
D.mature very slowly
3).According to the passage,the sawmills have to be mobile because they are ____.
A.floated up the rivers
B.transported near the markets
C.moved away from cleared areas
D.used to transport wood
4).According to the passage,relatively few trees are removed from the forests because ____.
A.only the most valuable justify the cost
B.the proliferation of species cannot absorb the high costs
C.the tropical hardwoods are expensive to produce
D.it is too expensive to transport the hardwoods
5).What can be assumed from the information given in the passage?
A.not enough species grow near the rivers.
B.useful species do not reproduce quickly.
C.too many species grow in the forests.
D.tropical forests produce too many trees.

1.The forests of the tropics produce a magnificent growth of trees,but commercial lumbering is inhibited by problems that increase the cost of removal.The proliferation of species that is common to all tropical forests creates difficulties because ma
1.森林的热带地区产生一个宏伟的成长的树木,但商用伐木业被问题的成本增加去除.扩散的物种热带森林都是一样的,因为许多物种造成困难是虚假的.那位伐木工人梳子森林,因此,切除有价值的树水源,方便流动他们到锯木厂下游.不幸的是,热带阔叶林倾向于生长缓慢,一旦允许地区需要大量的时间来恢复,迫使锯木厂成为移动.距离市场往往是相当大的程度,提高成本的交通工具.因为这些困难,只有最宝贵的树林能吸收高的相关成本生产.其他树木都完好如初.
1).根据文章,其中一个问题的商业采运___,那是哪个地区
答:选择有价值的树是很困难的
b几乎没有品种类型的树在森林
许多树被之无用的木材
d·很少硬木长在森林
2).伐木工人的搜索森林的树木和选择那些____.
热带植物是否
b .很容易割下来
c较近的河流
d·成熟的非常慢,
3).根据本文,有这个锯木厂是移动,因为他们是____.
答:飘了江河
在b .运输市场
远离空旷地区之
d·用于运输木头
4).根据本文,清除相对几棵树的森林,因为____.
答:只有最宝贵的证明了我们的成本
B.扩散物种无法吸收高成本
C.热带阔叶林是昂贵的生产
D.太贵了运输产硬木
5).能从承担所提供的信息这一段吗?
答:没有足够的物种生长在河流.
b有利用价值的种类不繁殖很快.
太多的物种之长在森林.
热带森林(产生了过多的树