I should say that the second question I posted was misleading. In fact I have been hesitating for the time being. It is hard to say I will go to Ca in the future even if I get my LP. In a word, it is uncertain for my choice for the rest of my life yet. That is why I ask those questions.
If I decide to withdraw my application, then I will not wasting my time on learning new things. My wife will try something new, but if we do not considering immigration, then her choice of study will also change. She will choose those major which will benefit her jobhunting in China. In a word, making a decision on immigration will be critical for us. We are not very young anymore.