听专业人士解释之后，我才发现自己真是太外行了。

Tīng zhuānyè rénshì jiěshì zhīhòu, wǒ cái fāxiàn zìjǐ zhēnshì tài wàiháng le.

Only after listening to the experts' explanation did I realize how much of a layman I really am.

我对电脑维修完全是外行，只能请专业的人来帮忙。

Wǒ duì diànnǎo wéixiū wánquán shì wàiháng, zhǐnéng qǐng zhuānyè de rén lái bāngmáng.

I'm a complete layman when it comes to computer repair and can only ask professionals for help.

在艺术方面，我只是个外行，看不出太多门道。

Zài yìshù fāngmiàn, wǒ zhǐshì gè wàiháng, kànbuchū tài duō méndào.

In terms of art, I'm just a layman and can't see many subtleties.