It is very important for us ________ English well.

The explorers failed to find the cave because it was not locatedthey had expected it to be.

year, millions ofpeople visit the Palace Museum, and many of __ are foreigners　

依次填入下面一段文字横线处的语句，衔接最恰当的一组是人类为什么要有底线为了生存。人，是社会的群居物。任何人，都不能一个人活在这世界上。 所以，只有让别人生存，自己才能生存；让别人活得好，自己才能活得因为底线是人类生存的基础 ，是最后一道好。 ， 。 ， 。 ， 。防线。基础不牢，地动山摇；防线失守，全盘崩溃。①境界不一定人人都有或要有②希望所有人都活得好，甚至为了别人的生存放弃自己的利益③这是“境界”④这是“底线”⑤底线却不能缺失⑥不妨碍别人的生存，不侵犯别人的利益，不破坏社会的环境

Tom was late for school ___________________, which, of course, made his teacher very angry.