Potential complement

Also known as: 可能补语 (kěnéngbǔyǔ) and complements of potentiality .

Potential complements are used to express the possibility of achieving an expected result in Mandarin.

Potential forms most commonly occur in negative statements. Affirmative statements using the potential form are somewhat uncommon, and, when they do occur, are usually answers to questions (or as rebuttals).

Formation of Potential Complements

For affirmative potential complements, 得 is placed between the action verb and the complement. For negative potential complements, 不 is placed between the action verb and complement. The structure of the potential form is:

V + 得/不 + complement

Putting 得 or 不 between an action verb and a result complement or direction complement changes them to potential complements.

Resultative, Directional and Potential Complements
Resultative Complement	Directional Complement	Aff. Potential Complement	Neg. Potential Complement
做完		做得完	做不完
听懂		听得懂	听不懂
	起来	起得来	起不来
	爬上来	爬得上来	爬不上来

Objects with potential complements

Objects in sentences with potential complements can occur either after the complement or at the beginning of a sentence

Objects occurring at the beginning of a sentence with a potential complement
Object	Subject	Complement Phrase
这个汉堡	我	吃得完
山	他	爬不上来

Objects occurring at the end of a sentence with a potential complement
Subject	Complement Phrase	Object
我	吃得完	这个汉堡
他	爬不上来	山

Contrasting Degree Complements with Potential Complements

Some sentences that contain adjective complements may be indistinguishable as degree or potential complements when they are taken out of context. For example 跑得快, 说得清楚. The following scenarios put these examples in a context and distinguish them as potential and degree complements.

Potential Complements
A:他跑得快，跑不快？
B:他跑得快。

A:她能说得清楚吗？
B:他说不清楚。

Degree Complements
A: 我的朋友跑得很快，他呢？
B:他跑得快。

A:她说得清楚还是说得不清？
B:她说得清楚。

Degree complements commonly are directly preceded by an adverb (他输得很清楚) distinguishing them from potential complements which never directly preceded by an adverb.