变迁【biàn qiān】
1. change 2. change; vicissitude
[动]1、指事物的逐步变化及转移 [名] 2、变化

气候变迁和环境恶化给社会带来了很多问题。
The change of climate and the deterioration of environment have lead to many social problems.

这本史书详细地记述了时代的变迁。
The history book recorded the details of the vicissitude of times.
变形【biàn xíng】
1. be out of shape; become deformed 2. change from man to animal or vice versa
[动]1、形状、格式起变化 2、童话或神话故事中指人变成某种动物的形状或动物变成人的形状

这个箱子很结实,不容易压变形。
The box is rather strong and is not easy to be crushed out of shape.

王子被巫婆施法后,变形成了一只青蛙。
The prince turned into a frog under the witch's spell.
变质【biàn zhì】
deteroprate; go bad
[动短]人的思想或事物的本质变得与原来不同(多指向坏的方面转变)

为了防止食物变质,最好把它放在冰箱里。
The food should be kept in fridge in case it goes bad.