Scholars of human migration speak of two main factors that influence an individual’s decision to move from one place to another-push and pull factors. Push factors are associated with the place of origin. A push factor can be as simple and mild a matter as difficulty in finding a suitable job, or as traumatic as religious persecution, war, or severe famine Obviously, refugees who leave their homes with guns pointed at their heads or with hate-filled mobs at their heels are motivated almost entirely by push factors (although pull factors do influence their choice of destination).
Pull factors are those associated with the place of destination. Most of these are economic, such as better job opportunities or the availability of good land to farm. The latter was an important factor in attracting settlers to the United States during the nineteenth century. In general, pull factors add up to an apparently better chance for a good life and material well-being than is offered by the place of origin.
Besides push and pull factors, there are what the sociologists call " intervening obstacles " . Even if push and/or pull factors are very p, they still may be outweighed by intervening obstacles, such as the distance of the move, the trouble and cost of moving, the difficulty of entering the new country, and the problems likely to be encountered on arrival.
The decision to move is also influenced by " personal factors " of the potential migrant. The same push-pull factors and obstacles operate differently on different people, sometimes because they are at different stages of their lives, or just because of their varied abilities and personalities. The prospect of pulling up stakes and moving to a new and perhaps very strange environment may appear interesting and challenging to a young, footloose man and appallingly difficult to a slightly older man with a wife and young children. Similarly, the need to learn a new language and customs may intrigue one person and frighten another.
Regardless of why people move, migration of large numbers of people causes friction. The United States and other " receiving countries " (the term used for countries that welcome large numbers of migrants) have experienced adjustment problems with each new wave of immigrants. The newest arrivals are usually given the lowest-paying jobs and are resented by natives who may have to compete with them for those jobs. It has usually taken several decades for each group to gain acceptance in the mainstream of society in the receiving country.
Refugees migrate out of their country probably because of（）
A. their country’s unstable situation
B. bad economic conditions
C. guns pointing at them
D. their resentment towards government
参考答案：A
解析：
推断题。第一段第三、四句提到“A push factor can be as simple and mild a matter as difficulty in finding a suitable job, or as traumatic as religious persecution, war, or severe famine. Obviously, refugees who leave their homes with guns pointed at their heads or with hate filled mobs at their heels are motivated almost entire by push factors.”(推动因素可以是简单而温和的，如难于找到一份合适的工作；也可以是伤害性的，如宗教迫害、战争或者严重的饥荒。显然，那些被人用枪指着头或是被那些满怀恨意的暴徒追赶而离开家园的逃亡者，则几乎全都是由于推动因素而移民的。)句中“with guns pointed at their heads or with hate filled mobs at their heels”隐含的意思就是国家的局势不安定，因此A项正确。文章提到逃亡者被人用枪指着头离开家，但这是为了说明国家局势不稳定而举的一个例子，并非离开家的最主要原因，故排除C项；B项和D项均与文意不符，因为有关难民的内容仅在首段第四句提到，此处没有提到经济问题和对政府的愤恨。