Thank everyone for helpful response. The situation is that: the EF 70-200 lens can still focus quite smoothly, all apertures function as it should. I can see a big water stain inside of front element. However, the pictures from this foggy lens are still amazingly good. So I am wondering in this situation if I spend $200 to just clean the element, it maybe still worth to do it.
The EF 50mm/1.4 lens, when I received it, it still worked well, and only minimium stain inside of it. However recently I found AF was not working any more, I don't know why.
I opened the EF 17-35/2.8L, and found some cable was broken, probably my friend already did something about it.
The EOS 3, I found the LED in the viewfinder can't show the exposure colume, other information can still show up. The problem I found is the battery leakage.