Pal cannot play ntsc.
Wrong. There are two main differences between (most) PAL and NTSC versions of the same game: The PAL version displays more scanlines, so it runs at 50 Hz, and the PAL version uses different colo(u)rs, because the PAL and NTSC TIA chips in the consoles have their colo(u)r tables in a different order and the PAL version has fewer colours. Otherwise, a console doesn't care what region of cartridge you put in it. A PAL console will run NTSC games just fine. Colours will be incorrect and some games might be hard or impossible to play for that reason, but most games will play fine.
Another thing people who play games from both regions may notice: most PAL version games run slower than their NTSC counterpart, because when the programmers added the extra scanlines, they didn't bother to change the sprite speeds to compensate for the slower 50 Hz framerate.