Comma use before "then"?

Clauses can become tricky, consider the following sentence.

Professor Smith enters the portal then disappears.

I am unsure if the above sentence requires a comma after the word portal.

What is the proper method to use with the English language?

A. Professor Smith enters the portal then disappears.

or

B. Professor Smith enters the portal, then disappears.

I am trying to avoid the common "and then'' since screenwriting only uses "and" with items/things or two characters.

Example: 

Carol and Bob walk to the door.

Bob holds a book and pencil.

Thank you in advance.

3 Answers

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  • Zirp
    Lv 7
    1 month ago

    clarity requires a comma, yes

    Professor Smith enters, the portal then disappears.

    Professor Smith enters the portal, then disappears.

    • Kazoo M
      Lv 7
      1 month agoReport

      The fixed portal cannot disappear. Therefore, I will use the second example; bravo!

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  • 1 month ago

    Yes, put a comma. See Merriam Webster example sentences. Then is not a conjunction BTW.

    • Kazoo M
      Lv 7
      1 month agoReport

      I entered the sentence in Grammarly, both variations pass, of which confuses me.

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  • Anonymous
    1 month ago

    No comma is called for because "then" is a conjunction introducing an additional verb, "disappears," to the main clause, it sharing "Professor Smith" as its subject with "enters." However, even if you gave it its own subject (e.g., "then he disappears), it would still not call for a comma because "then" is a subordinating conjunction and subordinating conjunctions that introduce subordinate clauses after the main clause don't call for a comma beforehand to separate them from the main clause like coordinating conjunctions introducing coordinate clauses do, the only exception being when the subordinating conjunction is introducing a subordinate clause that is thematically contradictory of the main clause. 

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    • Days of You’re
      Lv 7
      1 month agoReport

      The top example sentence on Merriam Webster is: "[He] walked to the door, then turned". This proves your answer is incorrect.

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