买一套好服装是值得的，因为它比便宜的要耐穿。

[误] It is worth to buy a good suit because it will wear better than a cheap one.

[正] It is worth buying a good suit because it will wear better than a cheap one.

注：在 it is worth buying 的句型中，worth 是形容词，习惯上不跟动词不定式，而跟动名词，或者跟名词或代词。