由问题请教各位牛人

丑小丫UID: 2135670

请教各位牛人：我有语法不明白   谢谢

the developed counties of the world are using up valuable resouces at a

precedented human history
为什末选precedented human?


in the initial planning for threaters,auditoriums, but any room intended primarily for listening ,acoustics is a major consideration

为什末选择but?


basalt ,which composes most of the ocean floor,is a drak-grey rock rich in iron and magnesium than most surface rocks

为什末选择rich ?而不选择floor?



found in the shells of lobsters ,shrimps and crabs, glucosamine is also present in human cartiage,which covering the bones in joints

为什末选择covering ?

the poor condition of prisoners are what concerned dorothea dix,an american social and director of a shcool in boston

为什末不选择concerned? 难道特没错吗？  我知道应将are 改为 is



leaning that takes place in fancy provide the           for the eventual transformation of a chlid into a adulit

necessary in the foudation
foudation necessary

为什末不选择第一个答案？

li_jingyunUID: 2131719

几乎所有的题目在精华区的语法笔记里面都有解释呢。