Continued from previous diagram. 4. ... Nxd5 is partially forced and Black does it. Now we return to white, what are the options for white?
I think White's options should be seizing the centre with 5-e4 or not seizing it by 5- e3 or 5-g3 or 5- Nf3
thanks mzo2014. It's been a useful discussion.
thank you i really Knew things I didn't know before,and they are useful things