语法填空,阅读下面的短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式。
As we all know, there are some differences between American English and British English. How did these differences take place? There is no quick answer ___ this question.
Actually at first the language in Britain and America was the same. After America became an independent(独立的) country, the language gradually began to change. For a long time the language in America stayed the ____,  while the language in England changed.
Over the centuries, a number of words and meanings ___ are still in everyday use in the United States have ____ (disappear) in British English. For example, American English still use the ___ (express) “I guess” (meaning “I think”), just as the British did 300 years ago.
In 1828 Noah Webster published the first American dictionary. To make American English different from British English, he changed the spelling of many words. That’s ____ the words colour, centre and traveller are ___ (spell) color, center and traveler in American English. Except for these differences in spelling, ____ (write) English is nearly the same in both British English and American English.
The differences are much ____ (great) in the spoken language. However, most of the time, people from the two countries do not have difficulty in ___ (understand) each other.