when I create a lake, water in the lake was not visible
then, I try to check the video on youtube for how to create a lake correctly,
but the way that on the video is the same way I make it.

please help!

I had the same problem, look in the optoins menu and it has some options for water in their. I can't remember what I did but it worked.
Coasteriffic

Its the common problem with everyone. I had tried to create a water body in guest mode and it worked. Try it....

Its the common problem with everyone. I had tried to create a water body in guest mode and it worked. Try it....

Um, what? Are you another bot?

You might be missing a patch

^ Probably what ArmadaBack said, or, Do you have a Mac? Water problems have been known to exist on Macs.