题目

There are several ways you can find out about the countries and places you wish to visit. You can talk to friends who have travelled to the places. Or you can go and see a colour film. Or you can read travel books. It would seem that there are three kinds of travel books. The first are those that give a personal, subjective(主观的) account of travels which the author has actually made himself. if they are informative and have a good index(索引), then they can be useful to you when you are planning your travels. The second kind are those books whose purpose is to give a purely objective( 我们的地球越来越热，全球平均海平面持续升高、冰川持续消融、极端天气加剧。导致全球气候变暖的主要原因有①臭氧层破坏　②森林被大量砍伐　③二氧化碳排放量增加　④二氧化硫排放量增加A.①②B.②③C.③④D.①④