一个三位数除以9余7，除以5余2，除以4余3，这样的三位数共有( )个。
A．5
B．6
C．7
D．8
参考答案：A
解析： 除以4余3说明此数末尾数是奇数，除以5余2说明此数末尾为2或7，综合可知此数末尾为7，因为此数减去7后是9,5,4的公倍数，即180,360,540,720,900，所以符合题意的三位数是187,367,547,727,907，故选A。
| Since life began eons ago, thousands of creatures have come and gone. Some, such as the dinosaurs, became extinct due to naturally changing ecologic conditions. More recent threats to life forms are humans and their activities. Man has drained marshes, burned prairies, dammed and diverted rivers. Some of the more recent casualties of man’s expansion have been the dodo, great auk, passenger pigeon, Irish elk, and Steller’s sea cow. Sadly, we can no longer attribute the increasing decline in our wild animals and plant species to "natural" processes. Many species are dying out because of exploitation, habitat alteration or destruction, pollution, or the introduction of new species of plants and animals to an area. As mandated by Congress, protecting endangered species, and restoring them to the point where their existence is no longer jeopardized, is the primary objective of the U.S. Fish and Wilidlife Service’s Endangered Species Program. |
Which of the following would be a likely theme for the next paragraph
A．Naturally changing ecological conditions
B．Animals that have become extinct
C．Achievements of the government Endangered Species Program
D．Programs that have destroyed natural habitats