What Is Their Main Difference?
Similarities and Differences
Parts of Speech
'Once' and 'since' have the same parts of speech. They are conjunctions. Conjunctions have three types and 'once' and 'since' are classified as subordinating conjunctions.
'Once' and 'since' are subordinating conjunctions of time.
Take a look at the following examples:
I will call you
It was his first public appearance
Talking about Time
'Once' and 'since' are used to express time.
- 'Once' is used to show that as soon as something happens, another action or event follows.
She got herself a Hotdog
She is a cool person
- 'Since' expresses an action that happened at one point in the past and continued happening until now (the present).
It has been two years
It has been so long
Talking about Cause and Effect
We use 'since' can be used to replace and mean 'because.' It can express cause and effect. Have a look:
He chose to walk
They decided to cancel the trip plan
Are They Interchangeable?
The answer is no. If we replace 'once' and 'since' with each other the meaning of the sentence completely changes.