它的意思应该是如果你已经是美国的税务居民，你就是加拿大的非税务居民。供大家讨论
Were you a deemed non-resident of Canada in 2016?

You were a deemed non-resident of Canada in 2016 if you would have been considered a resident of Canada (or a deemed resident) but, under a tax treaty, you were considered a resident of another country. You become a deemed non-resident of Canada when your ties with the other country are such that, under the tax treaty, you would be considered a resident of that other country and not Canada. In this case, the same rules that apply to a non-resident of Canada will apply to you as a deemed non-resident (including the way you complete your return).