Natural resources（资源）come from the earth．And they are limited．This means that they will not （41） 　　forever．Some are renewable，like trees，for example，you can plant a new tree when you （42） 　　one down．Others are not renewable，like the coal（煤）．Once it is dug out of the （43） 　　and used．it is gone．People realized the （44） 　　that the earth's natural resources are limited，and they decide to do something to help save （45） 　　．When you try to save one kind of natural resources，you had better use less of it，（46） 　　it will be used up so fast．One way that people save the fuel（燃料），such as gasoline，it's by riding a bicycle or working when the （47） 　　is short instead of driving．Water is a very important kind of natural resource because we all needed to keep （48） 　　．We can save water by making sure that our pipes and taps do not leak（漏）．We can also make （49） 　　 choices to save water，like only using the dishwasher or washing machine，not making the water keep running．Everyone can make contribution to （50） 　　natural resources．

41．A．last	B．spread	C．burn	D．change
42．A．turn	B．cut	C．put	D．move
43．A station	B．building	C．ground	D．house
44．A．news	B．plan	C．decision	D．fact
45．A．them	B．it	C．that	D．one
46．A．and	B．but	C．or	D．so
47．A．money	B．space	C．place	D．distance
48．A．alive	B．along	C．asleep	D．awake
49．A．generous	B．funny	C．wise	D．stupid
50．A．protecting	B．wasting	C．using	D．making．