Correct

添一张嘴

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Strokes
https://i.cchatty2.com/filters:format(webp)/fit-in/684x0/img/202102/添一张嘴-Chinese-idioms-Cchatty-c80e5fc4-5cc1-4b0c-9bcb-3ff3facc8f0f-1612777648.jpg

Collocation

1
添了一张要吃饭的嘴
2
添了一张嘴
3
不想添一张嘴
4
给家里添一张嘴
5
再添一张嘴
6
又添一张嘴

Definition

添一张嘴

Literally means:

have one more person to feed

Actually means:

have one or another child

It refers to having another family member to feed. It is often used to show that the living expenses on one more person, a baby for example, will bring much burden to the family when they suffer from poor financial condition or insufficient time or energy. It connotes that such burden should be reduced to the minimum.

指多一个人吃饭。多用来指在经济不宽裕或精力不足的情况,如果多负担一个人的生活,比如养孩子,就会增加很多负担。含有应尽量减少这种负担的意味。

Example

Used as predicate, object or attributive, and it car can have other words in between. (作谓语、宾语、定语,中间可以插入别的词语)
1
men
他们
夫妇
de
zi
日子
běnlái
本来
jiù
guò
de
jǐn
紧巴巴
de
  
,
xiànzài
现在
jiā
家里
tiān
le
zhāng
yào
chīfàn
吃饭
de
zuǐ
  
,
zi
日子
jiù
gēng
hǎoguò
不好过
le
  

Their couple's life was already tight Baba, now the family added a mouth to eat, life is even worse.

2
men
他们
juéde
觉得
xiànzài
现在
yǎng
le
háizi
孩子
jiù
jiàn
gòu
lèi
le
  
,
gǎn
zài
tiān
zhāng
zuǐ
ne
  
?

They think it's tired enough to have a child now, how dare you add another mouth?

3
men
他们
zǒng
juéde
觉得
xiànzài
现在
shōu
收入
gòu
不够
duō
  
,
hái
shi
gěi
jiā
家里
tiān
zhāng
zuǐ
de
shíhou
时候
  
,
xiǎng
děng
sān
三四
nián
hòu
以后
zàishuō
再说
  

They always feel that the income is not enough now, is not to add a mouth to the family, want to wait three or four years later.