连词的复杂用法最近在做关于连词的练习,找了道比较难的,可以有人帮我做出答案吗?----people think of g

(When) people think of global travel,they think of expensive cruise ships or sightseeing tours to famous places.(However) global travel has changed a lot in recent years.Now not all travel is expensive (and) lack of money does't have to hold people back.(In) these days there is an enormous variety of possibilities for people of all interests.
Approximately 20 percent of all international travel is now nature travel,or ecotourism.Serious ecotourists are interested in preserving the environment (while) learning about wildlife.(And) many want to learn about a new culture.(Although) it's possible to be very comfortable on an ecotour many travelers choose to rough it (up) they don't expect hot showers,clean sheets,gourmet food,(or) air-conditioned buses.(Instead) they want to live as villagers do,they get around on bicycles,on foot,(travel) on the water.
(Some) people want a valuable experience abroad,they can study (and) volunteer at the same time.(As) they go to the vijnana kala vedi cultural center in india,they can study two subjects,among them indian music,dance,theater,cooking,(and) yoga.The tuition for these classes (with) room and board is very low (for) the participants volunteer one hour each day to reach English to children in the village.(Some) people are interested in science,(and) they can study specific science in a hands-on experience (as) they volunteer on a research project through the organization called EARTHWATCH.