After and before

 What is after? What is before?

After and before are either adverbs, conjunctions, or prepositions. When they refer to time, they have opposite meanings.

After means "later than ..."; before means "earlier than ...".

1. Prepositions

1.1. Prepositions of time

Ex: After the meal, I felt asleep.
Before 2004, there were few social media.

1.2. Prepositions of place

After and before cal also refer to place when we imagine that we are going on a journey:
Ex: "Where's the new stadium?" "It's in Fs 4420 Road. It's after the cinema and before the supermarket."

Note: After and before can also refer to alphabetical order or position in sequence. For example: N comes after M in the alphabet.

2. Conjunctions

After and before can introduce clauses. When they do this they're called subordinating conjunctions. [See Conjunction for more details]

2.1. Position

The after-clause and the before-clause can be at the beginning of the sentence or at the end of the sentence. For example:
A. My parents gave² me some money after I left¹ home.
Or: After I left¹ home, my parents gave² me some money.

B. We're going to have¹ breakfast before we go² to work.
Or: Before we go² to work, we're going to have¹ breakfirst.

(¹= first action; ²= second action)

2.2. Past time

In the cluases that describe the first action (¹), we can use the Past Perfect in place of the Past Simple. For example:
A. The school security guards searched² all the students after they had left¹ school.
B. My mother had cleaned¹ the house before her friends arrived².

Note: Buth the words after and before are enough to indicate which event happened first, whichever tense we use.

2.3. Future time

We use present form for future time in after- and before- clauses. For example:
A. I'll see you again before you return to England.
B. Sam's parents will continue to give him money after he gets married.

Note: In an after-clause the Present Perfect can also be used for talking about the future.
Ex: We will know the results of the election after the votes have been counted.

3. Adverbs

After and before are used as adverbs of time. After* means: "after this, after that". Before means: "before this, before that, before now". They go at the end of a phrase or sentence.

Ex: At last the war was over, and not long after*, the soldiers returned home. (after = "after the war was over")
Have we met before? (before = "before now")

Note: * Social usage: after as an adverb is informal; afterwards is regarded as more correct.

I hope this article helps. If you have any question, please leave a comment below.