Correct

三长两短

/ sān cháng liǎng duǎn / 
Strokes
https://i.cchatty2.com/filters:format(webp)/fit-in/684x0/img/202102/三长两短-Chinese-idioms-Cchatty-cc1dd97e-ecd8-418f-966d-b8db5a06f9ac-1612776164.jpg

Collocation

1
怕他有什么三长两短
2
要是有个三长两短
3
万三长两短有个三长两短

Definition

三长两短

Literally means:

three long, two short

Actually means:

It refers to an unexpected misfortune or accident. It may also mean a possible calamity. Derogatory.

意外的灾祸或事故。也只可能发生的死亡事故。具有贬义色彩。

Example

Used as object or adverbial adjunct. (作宾语、补语)
1
Nǐ
你
bù
不
néng
能
wǎnshang
晚上
yī
一
gè
个
rén
人
qù
去
nàxiē
那些
bù
不
ānquán
安全
de
的
dìfāng
地方
  
,
wànyī
万一
yǒu
有
gè
个
sānchángliǎngduǎn
三长两短
  
,
wǒ
我
zěnme
怎么
gēn
跟
nǐ
你
fùmǔ
父母
jiāodài
交代
  
?

You can't go to those unsafe places alone at night, in case there are three long and two short, how can I tell your parents?

2
Bìngrén
病人
gāoshāo
高烧
bù
不
tuì
退
  
,
yīshēng
医生
dānxīn
担心
tā
他
shāo
烧
chū
出
gè
个
sānchángliǎngduǎn
三长两短
  
,
yīzhí
一直
shǒu
守
zài
在
tā
他
shēnbiān
身边
  
。

The patient had a high fever, and the doctor feared that he had burned three long and two short and had been by his side.

3
Wèile
为了
fángzhǐ
防止
yǒu
有
shénme
什么
sānchángliǎngduǎn
三长两短
  
,
tāmen
他们
zhècì
这次
chūmén
出门
rénrén
人人
dōu
都
dài
带
le
了
shǒuqiāng
手枪
  
。

In order to prevent anything three long and two short, they went out this time with a pistol.