Iran and six world powers reached a landmark nuclear agreement in 2015, and as a result the country has witnessed far-reaching changes.翼人们集(jí )合的速度很快，分散的速(sù )度也不慢，不一会(🤲)儿，山洞里面变得空荡荡的，只剩下陈(chén )天(😡)豪跟翼(yì )人(🍻)酋长两(liǎng )个人。