1.都是可以的.
2.stop sb doing sth = stop sb from doing sth,意思是“阻止某人做某事”.
如:My parents would like to stop me (from) playing computer games.
3.stop sb to do sth也可以,但它不是固定短语,其意思是“主语拦住了某人,然后自己去做某事”.其中to do sth做目的状语.
比如:I stopped him to ask for help.
我拦下了他以向他求助.