【導(dǎo)讀】mountainintheworld?world.saltlakes.conversations.world?B:Qomolangma.world?B:Sahara.world?B:Caspiansea.world?B:Nile.oftheUS.oftheUS.country.informationin2a.today’sGreatWalltour.Tourist1:Howlongisthewall?If. Tourist2:Wow,that’samazing!Whydidthe. asbigasthis.Wall?getnearthetop.