读珠江三角洲和全国GDP增长曲线图,回答下列问题:
(1)在人均国内生产总值(GDP)的变化上,珠江三角洲地区和全国的趋势有何差异:__________________________________________________________________________________________________________________________________________________________________
(2)分析这种差异是在20世纪80年代中期后变大的原因:____________________________________________________________________________________________________________________________________________________________________________________________
(3)珠江三角洲的经济特点:_____________________________________________________________________________________________________________________________________
(4)珠江三角洲地区和港澳地区如何进行合作:_____________________________________________________________________________________________________________________