短文改错. 本题共有10处错误，请在原文中改正（满分10分）

My bicycle went wrong again. Tired with repairing it again and again, I decide to buy a new one. After school, I went to a shop locating in the center of the city with a friend called Jack. The black bicycle attracted my eyes as soon as we went into the store. It looked such cool that I could hardly wait to ride it. The shopkeeper told us that it is the latest bicycle. He wanted to charge me 800 yuan, that was too high for me. I just couldn’t afford for such an expensive one. Then I chose another one, which cost him only 200 yuan. It was not perfect, it was much better than the old one.

下列数据是高温下金属镁和镍分别与氧气进行氧化反应时，在金属表面生成氧化膜的实验记录：a、b均为与温度无关的常数。

请回答：

(1)金属氧化膜的膜厚y跟时间t所呈现的关系是______ （填“直线”“抛物线”“对数”或“双曲线”等类型）： MgO氧化膜的膜厚y属于___型；NiO氧化膜的膜厚y'属____型。

(2) Mg和Ni比较，哪一种金属具有更好的耐腐蚀性？答：___。其理由是____。