问题补充:
Recently, there is boom(繁荣)in population mobility and according to national population survey of , 17 percent of the population move every year.
A. the; a
B. a; the
C. /; a
D. the;/
答案:
A. the; a
(答案→)B. a; the
C. /; a
D. the;/
解析:考查冠词。第一空a boom泛指在人口流动方面的一次繁荣,故用不定冠词a;第二空the national population survey of 是特指的的国家人口调查,故用定冠词the。句意:最近根据国家人口调查,人口流动方面有一次繁荣,每年有17%的人口流动。故B正确。