17．There are many kinds of resources on the Earth．Four of them are very important．They are renewable，nonrenewable，human，and capital resources．
Renewable resources can be used again and again．They can be replaced within a short time．Some energy resources are renewable．The energy from the sun，tides，water，and wind is renewable．Also，trees and animals are renewable．But humans still need to take good care of them．We should not waste them at all．
Nonrenewable resources are limited in supply．Once we use them，they disappear forever．They can't be replaced．Many energy resources are like this．Coal，gas，and oil are nonrenewable．
Human resources are people and the skills they have．This also includes the knowledge and information that humans have．
People make products using renewable and nonrenewable resources．Machines are often used to produce goods．The machines and tools that are used to produce goods are called capital resources．
任务一：根据短文内容，从A、B、C、D四个选项中选出正确的选项，完成46-48小题．
46．A
47．B
48．D
A．renewable resources
B．nonrenewable resources
C．capital resources
D．human resources
任务二：根据短文内容，在第49-50题的空格处填入恰当的词，不超过三个单词．
49．knowledge and information
50．producegoods．
阶梯计算系列答案
