Correct

真是老外

/ zhēn shì lǎo wài /
Strokes
https://i.cchatty2.com/filters:format(webp)/fit-in/684x0/img/202102/真是老外-Chinese-idioms-Cchatty-fa885510-1866-4973-8d88-36562c9228b5-1612777832.jpg

Collocation

1
在……方面真是老外
2
可真是老外

Definition

真是老外:

Literally means:

real layman

Actually means:

老外, a layman, someone who is unfamiliar with a certain field.

This phrase means an emphasis on someone's utter lack of knowledge or experience in some field. Slightly derogatory.

老外,外行,指不熟悉。

真是老外,强调某人对某方面的事情确实不了解,不熟悉,没有经验。略含贬义。

Example

Used as predicate. (作谓语)
1
zhēnshi
真是
lǎowài
老外
  
,
zhēnpǐn
真品
hěn
bǎoguì
宝贵
  
,
dōu
bèi
guǎn
博物馆
shōucáng
收藏
le
  
,
zěnme
怎么
huì
chūlái
出来
mài
ne
  
?

You are really a foreigner, the real thing is very valuable, have been collected by the museum, how can it be taken out for sale?

2
Biè
kàn
yōngyǒu
拥有
hěn
de
企业
  
,
dànshì
但是
shēnghuó
生活
xiàng
一向
jiǎn
俭朴
  
,
chīwán
吃喝玩乐
zhè
tào
zhēnshi
真是
lǎowài
老外
  
,
lián
OK
卡拉OK
dōu
méi
guò
  

Don't look at him has a big business, but life has always been frugal, eating, drinking and playing this set is really foreigners, even karaoke has not been there.

3
hángshān
隔行如隔山
  
,
jiāoshū
教书
de
shì
zhēnshi
真是
lǎowài
老外
  
,
dàn
zuò
mǎimài
买卖
jiùshì
就是
zhuānjiā
专家
  

Interlased like a mountain, teaching things he is really foreigners, but do business he is an expert.