第164页 | 300 Days of Better Writing | 阅读 ‧ 电子书库

Day 167: Place a comma between coordinate adjectives.

Coordinate adjectives? When you have two adjectives that describe the same noun, they might be coordinate adjectives. Here is the test:

The order can be reversed without changing the meaning.The comma can be replaced with and without changing the meaning.

The explanation will be easier to understand with an example. Consider this sentence.

“I want to buy a small, inexpensive car.”

The two adjectives in question are “small” and “inexpensive.” They both describe “car.” Let’s see if they are coordinate adjectives.

Can we replace the comma with and without changing the meaning: “I want to buy a small and inexpensive car”? Yes.Can we reverse the order without changing the meaning: “I want to buy an inexpensive, small car”? Yes.

Based on this test, “small” and “inexpensive” are coordinate adjectives, so they need to be separated with a comma. What about this sentence?

“The popular American author will visit tomorrow.”

In this sentence, “popular” and “American” are not being used as coordinate conjunctions. They both describe “author,” but they don’t pass the test above. Thus, you don’t need the comma.