求翻译：在上一周我上土木工程材料课的时候，老师讲如何把两块钢板焊接在一起，当我听完课的时候，使我以前脑海中的好多概念发生了变化，我以前认为焊接是一件很简单的事情，我们每个人都会做的，但是事实并非如此。我们只是看到他们的表面，而没有了解他们的内在情况,因此，我们做什么事情都是需要付出努力的，没有什么事是没有努力就可以得到的，天上没有掉馅饼得事情。是什么意思？

Last week my class time on civil engineering materials, teacher talk about how the two steel plates welded together, the time course when I heard that I had in mind the concept has changed a lot, I used to think that welding is a very simple things each of us will do, but it is not. We only see them

In the previous week I taught at the time the civil engineering materials, teacher talk about how the two-piece steel welding, and when I heard the lesson time in the mind, so that I have had several concepts have changed, I think welding is a very simple thing, each and every one of us will do, but

On previous week me civil engineering material class time, how does teacher say two steel plates welds in together, when I listen to the class the time, caused me before in mind many concepts have had the change, I before thought the welding was a very simple matter, our each person could do, but th

Last week my civil engineering materials course days, the teacher how to two pieces of steel plates welded together, when I was right after the lecture, I used concepts have changed a lot of minds, I used to think that welding is a very simple thing, every one of us has done, but this is not the cas

Last week my civil engineering materials course days, the teacher how to two pieces of steel plates welded together, when I was right after the lecture, I used concepts have changed a lot of minds, I used to think that welding is a very simple thing, every one of us has done, but this is not the cas