If it changes console with Alt then it is getting the keypress. You might try out getting its keycode with xev and mapping it to proper Alt with xmodmap.
On 2016-01-09 03:54, Teng Zhang wrote:
hi, the Alt key doesn't work on my machine in most cases except forchanging console(Crtl+Alt+F_number). So, what key i can use to replace Alt.