You use before a non-specific item.
Hand me a fork. -- It can be any fork in the drawer.
You use the before a specific item.
Give me the fork. -- In context, it is clear to you which fork I want. If unclear, you'd ask, Which fork do you want?
Consider how these are different:
A teacher yelled at us.
The teacher yelled at us.
Maybe on the first one, you don't know the teacher or his name.
On the second one, it means one specific teacher, maybe your history teacher.
i do not know how to use embalming in a sentence. (there is the sentence)
So- you are asking when to use 'when' in a sentence. When you are asking how to use when in a question, you are already using when in a sentence, because a question actually is a sentence. I like to use when in a sentence whenever I like.
How do you use sedition in a sentence
use contingency in a sentence?
use adainty as sentence
use aver in a sentence
Can you use abstemious in a sentence?
use ize in sentence
This is how you use mound in a sentence
enjoin use in sentence
how can we use travelogue in the sentence
Use it in a big sentence.