若式子2-xx-1有意义,则x的取值范围为( )
Hearing the good news that he had been admitted into his dream university after so many years of hard work, his parents couldn't help b____ into tears.
下图为某国总人口和城市人口增长统计图。根据图中信息可知,目前该国人口增长模式最可能是( )