if & when

zero conditionals

문형: when/if 단순현재, 단순현재 

쓰임:
⒜ to talk about facts and truths, or a general situation that is true for everyone
⒝ when/if가 혼용되어 사용된다

The sous chef... there.
The sous is responsible for the kitchen 
when the chef's not around.

부주방장은... 저기요.
주방장이 없을 때 주방을 책임지는 사람이에요. 

'라따뚜이'에서

first conditionals

문형: when/if 단순현재, will+동사원형

쓰임:
⒜ to talk about a possible future situation and its possible result, which is specific or one-off
⒝ when/if가 혼용되어 사용되지 않는다. 화자가 미래에 어떤 일이 발생할 것으로 확실할 때는 when (certain to happen), 발생 여부 또는 진위 여부가 불확실한 일이나 상황을 언급할 때는 if를 쓴다 (likely to happen).

When I go to the shops, I'll get some bread.

(I'm definitely going to the shops)  

≠ If I go to the shops, I'll get some bread.

(I might not go to the shops)

But when I see the blood upon your door,
I'll pass over you, and the plague shall not enter. 

If for any reason the winner is unsuccessful,
the first runner-up will take his place and so on and so forth.