A complement is a secondary part of a sentence. It is placed after a predicate expressed by a verb or adjective, and expresses the speaker's view of the chance of success.
The simple directional complements consist of one character. The simple directional complements are expressed by directional verbs.
来 and 去 are the most commonly used.
If the action moves towards the speaker or comes closer in any way, use 来.
If the action moves away from the speaker or becomes more distant in any way, use 去.
Let's compare these complements:
"A" is on the first floor, "B" is on the second. "A" says to "B": 下来吧 .
来 is used because the action "to come down" would will be movement moved towards speaker "A", and "B" will come closer to "A".
"B" replies: 我不能下去 .
去 is used because speaker "B" will move away from where he is now.
"A" is in the house, "B" and "C" are outside this house. "A" says to "B": 进来吧 .
来 is used because the action "to come in" would be movement be movement moved towards speaker "A", and "B" will come closer to "A".
Someone will ask "C": "Where is "A"?", "C" will answer: A进去了 .
去 is used because "A" has become more distant from speaker "C".
If there is an adverbial modifier of place or an object in the sentence, they are placed between the verb and the complement 来/去.
The predicate is "divided".
adverbial modifier of place
Come into the classroom
jìn jiàoshì lái
I want to bring my backpack
wǒ xiǎng dài bèibāo qù
进来教室 or 带去背包 are not used.
If there is both an adverbial modifier of place and an object in the sentence, the structure is:
Bring a chair upstairs
ná yǐzi lái lóu shàng
了 is used only as a particle at the end of a sentence.
Other directional complements
Let's consider the other directional complements.
进 — the direction of a movement going from outside to inside.
走进 渗进 出 — the direction of a movement going from inside to outside.
拿出 上 — the direction of a movement going from low to high.
登上 跳上 下 — the direction of a movement going from high to low.
放下 垂下 回 — movements that are coming back or returning.
带回 取回 过 — movements that come across or go across.
跑过 钻过 起 — the direction of a movement going upwards.
Let's compare 起 and 上:
上 indicates movement in space, and can be used with an adverbial modifier of place.
起 has the meaning of "to move upwards from the surface". 起 cannot be used with an adverbial modifier of place.
An adverbial modifier of place and an object are placed after a complement (except 来 and 去) and a verb.
to run downstairs
to take out a notebook
了 can be used as a particle at the end of a sentence and as a suffix after the verb.
It is not always necessary to use complements. If we are talking about the movement itself or the purpose of the movement, it is enough to use only a verb. Complements are necessary to clarify the direction.
孩子跑了 — the direction is unknown. What is more important here is how the child moves: he runs.
孩子跑来了 — 来 indicates that the running was directed towards the speaker.
没 or 没有 is placed before the predicate to negate a sentence.
They didn't bring their passports
tāmen méi dàilái hùzhào
We didn't go home
wǒmen méiyǒu huíjiā qù
The negative adverb 不 is used only in conditional sentences and before modal verbs.