Sometimes in Chinese you see the particle 的 (de) after adjectives, but
sometimes you don't. What is the rule for whether or not you should put 的 after
an adjective?
As usual with Chinese grammar, there isn't a 100% concrete rule for this, but
there is a strong guideline. In general, you need to put 的 after a two-syllable
adjective, and should not put it after a single-syllable adjective.
As always, remember that there can be exceptions to these “rules”. They are just
useful guidelines that help you get a better sense of the language. Always
include lots of listening and reading in your learning diet to get a real feel
for Chinese.
Don't put 的 after single-syllable adjectives
In general, you should not put 的 after a single-syllable adjective. Adjectives
with just one syllable can usually be placed directly before a noun to modify
it. Some examples:
The words above are actually more like compound nouns that function as
individual units. There's no need to separate them with 的. You might use these
words in sentences like these, for example:
我很喜欢吃辣菜。
Wǒ hěn xǐhuan chī là cài.
I really like eating spicy food.
他是好人。
Tā shì hǎorén.
He's a good person.
那个城市帅哥很多。
Nàgè chéngshì shuàigē hěnduō.
There are a lot of handsome guys in that city.
As you can see, these words are really just compound nouns consisting of an
adjective that modifies a noun. You don't need to put 的 after these
single-syllable adjectives.
Do put 的 after multi-syllable adjectives
If you add in extras that make the adjective longer, then you have to use 的.
For example, if you put 很 (hěn) in front of the adjective to intensify it, it's
now two syllables and you should put 的 after it.
Some examples:
很坏的人
hěn huài de rén
very bad person
十分大的房子
shífēn dà de fángzi
very big house
非常贵的车
fēicháng guì de chē
extremely expensive car
The adjective in this structure can be as long as you like, or even be replaced
with a more complicated phrase, and still be used to modify the noun. All you
have to do is put 的 in between.
As well as adjectives that have been modified and become multi-syllable, there
are also adjectives that are multi-syllable on their own. These should also have
的 after them when used to modify nouns. Some examples:
好看的人
hǎokàn de rén
good-looking person
红色的衣服
hóngsè de yīfú
red clothes
舒服的椅子
shūfú de yǐzi
comfortable chair
友好的老师
yǒuhǎo de lǎoshī
friendly teacher
The only rule you have to remember is that if the adjective is one syllable, you
usually don't put 的 after it. Otherwise, no matter what the
adjective is, you should usually use 的.