什么样才属重大变化呢? 恳请小白兔见内详情再指点.

上次邮寄签证申请到BUFFALO时,表上填了我们已申请加拿大移民. 附了母亲六月份从美国回中国的机票. 她只是想跟我们登陆加拿大时去看望舅舅,然后回美. 不料加拿大签证官以如下理由拒签:
1. You have not satisfied me that you meet the requirements of Regulation 179; that you would leave Canada at the end of the temporary period if you were authorized to stay. In reaching this decision I considered your ties to your country of residence/citizenship balanced against factors which might motivated you to stay in Canada.
2 You have not satisfied me tha you would leave Canada at the end of your stay as a temporay resident. In reaching this decision, I considered several factors, includig:
you family ties in Canada and in your country of residence
Purpsoe of visit
万分感谢热心的小白兔, 如果提供中国房产证明, 存款证明并说明父亲还在中国, 理由算充分吗? 本以为加拿大签证容易上次就没提供以上文件. 哎, 轻敌了!
要是面签还有希望,我们应该准备或注意什么呢?万分感谢!