1. Can you finish the work by five oclock?
你五点钟前能完成工作吗？
2. By this time next week well be in New York.
下星期的这时大家将在纽约。
3. By eight oclock he had arrived at my hotel.
到8点时，他已经到达我住的宾馆了。
By引导的时间状语，有时表示 在...之前，有时却表示 在...时候
请问老师怎么样区别？以下遇见一题让我感觉不知所措。
课文原话By the time you read this, the Hubbles eagle eye will have sent us thousands and thousands of wonderful pictures.
题目：________you read this, thousands of pictures will have been sent to us.
A. The moment B. Before C. When
正确答案是：B
为何不可以用A和C呢？
课文原话：By the time you read this, the Hubbles eagle eye will have sent us thousands and thousands of wonderful pictures.
题目：________you read this, thousands of pictures will have been sent to us.
A. The moment B. Before C. When
正确答案是：B
为何不可以用A和C呢？
【答】从网友提供的材料看，是想证明：before + 从句 = by the time + 从句。
我觉得，这两种表达不对等。因此，原正确答案并不正确：
Before you read this, thousands of pictures will have been sent to us. （误）
正确的表达是：
By the time you read this, thousands of pictures will have been sent to us.（正）
Before you read this, thousands of pictures will be sent to us.（正）
其余两个答案同样错误。
【特别提醒】注意每一个句子的红色部分，通过对比，即是否了解错在哪儿。
解决这个问题的重要是，学会by the time 和before 的根本不同：
前者表示“时间段 + 截止点”之前；
后者表示“时间点”之前。
