菜鸟问题之小小语法English today is very different from the English sp

菜鸟问题之小小语法
English today is very different from the English spoken long,long ago.By the 12th century,the language has already changed very much.People then could not read the writings from the year 700.The history of the English has three parts--"Old English"(before the year 1150)."Middle English"(up till 1500) and "Modern English"(1500 to now).
The biggest difference from Old,Middle and Modern English is in vocabulary.Grammar has not changed greatly.But thousands of new words have come into the language.Many of these are from French.
Another important change is pronunciation.It has changed so much that there are almost no words said the same way today as in Old English.
1:by the 12th century中的BY是固定搭配么?可否用其它介词来代替么,能用哪些来代替呢?
2:the year 700中的the year为什么指的是公元?它还能表示其它的么?
3:the biggest difference between Old,Middle and Modern English is in vocabulary.为什么是in vocabulary?如果没了in会一样么?有in 和没in的分别在哪呢?