我有2个问题想请教大家，麻烦大家告诉我为什么 感谢大家帮忙
1
The education of "bilingual" students in the U.S. has always been closely 39
political, economic and socialconcerns. As a nation of immigrants, the U.S.
was founded by colonists from multiple language backgrounds andnationalities.
______ early private schools were quickly established to teach colonial children,
schools were generallysegregated by communities so that students studied in
their native languages. As immigrant communities (mainly fromEurope) vied for
political and economic power in the new world, language and nationality
differences raised tensionsbetween neighbors.
A) Because B) Since C) Unless D) While 答案是D
请问为什么不能用A或B，而是用while?
2
The Johnsons______ to Japan for a 5-day vacation last week, but their trip
was cancelled due to the terribleweather conditions.
a) were going B) had gone C) did not go D) could not be going 答案是A
请问我的想法是C，他们一家人没去，行程还会因为天气取消
我不懂为什么他们去了，行程还会取消?

第一题选AB你可以试着翻译吗？ http://imgur.com/f5ljxom第2题 C 也可以试着翻译看看？

1.while是although的意思2.but后面说行程被取消，所以前面说“计画”要去日本，语意才通顺。若是C，前面变成上周没去，后面又有个but子句，其意义并非与前面子句转折，语意不通顺。

第二题 were going to 本来计画要去 的意思选c 的话，本来就没有要去 就不会因为天气而取消了

谢谢大家