alter v.使事物在外观、性质、用途等方面稍作改变。
the tailor altered the waistband on my pants because it was too tight.
.裁缝修改了我的裤腰因为它太紧了。
modify v.改变，修改，以使某物更趋完善，还可以用来表示态度、脾气、意见变得温和。
he was loud and angry, and his friends told him to modify his behavior.
他粗声大气，脾气暴躁；朋友们告诉他要改变自己的举止。
transform v.指彻底、深远的改变，这种变化完全改变了外观或特性，使被改变的对象脱胎换骨。
remodeling transformed an old, dark houses into so cheerful one.
重新装修使这所陈旧昏暗的房子变得赏心悦目。
vary v.强调没有一定规则、陆续的变化或差异。
air fares vary from one airline to another. 航空公司的机票价格各不相同。