英语翻译

英语翻译
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.
我应该怎么样理解句子
句子A:People then could not read the writings from the year 700.
句子B:It has changed so much that there are almost no words said the same way today as in Old English.
为什么这2句子给我的感觉好像现在时和过去时混着用似的?