In 1907, or so it has sometimes been written, Albert Einstein saw a workman fall off a roof and began to think about gravity.
1907年，反正有时候书上是这么写的，有个工人从房顶上掉了下来，爱因斯坦就开始考虑引力的问题。
Alas, like many good stories this one appears to be apocryphal.
天哪，像许多动人的故事一样，这个故事的真实性似乎存在问题。
According to Einstein himself, he was simply sitting in a chair when the problem of gravity occurred to him.
据爱因斯坦自己说，他想到引力问题的时候，当时只是坐在椅子上。
Actually, what occurred to Einstein was something more like the beginning of a solution to the problem of gravity,
实际上，爱因斯坦想到的更像是开始为引力问题找个答案。
since it had been evident to him from the outset that one thing missing from the special theory was gravity.
他从一开头就清楚地认识到，狭义相对论里缺少一样东西，那就是引力。
What was "special" about the special theory was that it dealt with things moving in an essentially unimpeded state.
狭义相对论之所以“狭义”，是因为它研究的完全是在无障碍的状态下运动的东西。
But what happened when a thing in motion—light, above all—encountered an obstacle such as gravity?
但是，要是一个运动中的东西——尤其是光——遇到了比如引力这样的障碍会怎么样？

It was a question that would occupy his thoughts for most of the next decade
在此后10年的大部分时间里，他一直在思索这个问题，
and lead to the publication in early 1917 of a paper entitled "Cosmological Considerations on the General Theory of Relativity."
最后于1917年初发表了题为《关于广义相对论的宇宙学思考》的论文。
The special theory of relativity of 1905 was a profound and important piece of work, of course,
当然，1905年的狭义相对论是一项深刻而又重要的成就。
but as C. P. Snow once observed, if Einstein hadn't thought of it when he did someone else would have, probably within five years;
但是，正如C.P.斯诺有一次指出的，要是爱因斯坦没有想到，别人也会想到，很可能在5年之内。
it was an idea waiting to happen.
这是一件在等着要发生的事。
But the general theory was something else altogether.
但是，那个广义相对论完全是另一回事。
"Without it," wrote Snow in 1979, "it is likely that we should still be waiting for the theory today."
“没有它，”斯诺在1979年写道，“我们今天有可能还在等待那个理论。”