In American English, then and than are sometimes pronounced alike. This can be quite confusing for an ESL student.
Both than and then are very common in both speech and writing. Than is a subordinating conjunction. It is only used to make comparisons.
- She is taller than you.
- They are richer than us.
- Some people believe that they are more important than others.
Than is also used in the adverbial construction ‘other than’.
- Other than Martin, no one bothered to turn up. (= Only Martin came.)
Pronouns after than
After than we usually use object pronouns.
- She is taller than him. (NOT She is taller than he.)
- You are better than her. (NOT You are better than she.)
Subject forms should be used if the pronoun is followed by a verb.
- She is taller than he is.
Then is essentially an adverbial conjunction. It means ‘next’, ‘after that’ or ‘afterwards’. It is different from a typical conjunction in that it can move around in the sentence. A typical conjunction, on the other hand, cannot change its position in the sentence.
- We will go to Paris first, then we will visit Rome.
- We will go to Paris first, we will, then, visit Rome.
- We will go to Paris first, we will visit Rome then.
As you can see the word then can move around within the clause.