Day 65: Use a hyphen for compound, selfmodifying, descriptive word pairs before a noun.

This really isn’t as complex as it sounds. Consider this sentence.

“The sky-blue paint complimented the office furniture.”

The term “sky-blue” has two words, so it is compound. The word “sky” modifies, or describes, “blue,” so these words are self-modifying. The word pair “sky-blue” describes and comes before the noun “paint.” Thus, it needs a hyphen. Here’s another example.

广告：个人专属 VPN，独立 IP，无限流量，多机房切换，还可以屏蔽广告和恶意软件，每月最低仅 5 美元

“The well-known actress woke up in jail.”

The term “well-known” has two words, so it is compound. The word “well” describes “known,” so these words are self-modifying. The word pair “well-known” describes and comes before the noun “actress.” Thus, it needs a hyphen.

If you put “sky-blue” and “well-known” after the nouns they modify, you don’t need the hyphen. For example, you don’t need a hyphen if you write “The paint is sky blue” or “The actress is well known.”