题目

There are camels from  Africa and Asia．This is an African camel．It lives in the desert and eats grass．It doesn't often drink． The monkey comes from South America．It’s South American．The monkey lives in the jungle and eats fruit．There are elephants from Africa and India．This is an Asian elephant．It lives in India．In Asia, some elephants work in the forest．Elephants like water． There are snakes in Asia,  America,  Africa, Australia and Europe．This snake comes from America．It eats meat．It doesn't like water．  The kangaroo comes from Australia．It’s Aust根据下列语句，分别设适当的未知数，列出二元一次方程或方程组： (1)甲数的比乙数的3倍小5； (2)甲、乙两数的和是3，且甲数比乙数的20％大13． (3)摩托车的时速是货车的倍，它们的速度之和是200km/h． (4)某种时装的价格是某种皮装的价格的1.4倍，5件皮装比3件时装贵700元．