Question

it was evening__we reached the little town.A that B until C

Answer 1

C

我们还没到小镇天就黑了.

这不是强调句,因为强调句有一个特点,就是去掉强调结构It is/was...that句子意思及结构仍然完整.这句话如果去掉这个结构就成了：

We reached the little town (in the) evening.也就是少了in the

所以排除A.

如果选B意思不通.“直到我们到达小镇天黑了.”

如果要表达“直到我们到达小镇天才黑”,应该用not.until

It was not evening until we reached.

选C,从字面意思上看是在我们到达小镇前,就已经是晚上了.也就是：我们还没到小镇天就黑了.