No Comma Between a Subject and Its Verb

A sentence needs a subject and a verb, and those two parts are glued together. No punctuation mark goes between them, not a comma, not anything else. This feels obvious with a short subject like 'The dog barks.' Nobody writes 'The dog, barks.' But stretch the subject out to twelve or fifteen words, and the itch to drop in a comma gets strong. The rule hasn't moved, though. A fifteen-word subject is still a single subject, and the verb still has to touch it directly.

The trick is bracketing. Find the whole subject first, from its very first word to its very last, before you even look for the verb. Put mental brackets around it: [The reason the seeds float] is that their plumes create drag. Whatever sits inside those brackets, however many clauses or prepositional phrases are stuffed in there, counts as one unit. The verb comes immediately after the closing bracket, with nothing in between. This works even when the subject is itself a clause, like 'What the survey team found under the meters of silt.' That whole clause is the subject, so the verb 'changed' follows it with no mark at all.

This sits inside the larger idea that punctuation inside a sentence has to mark a real grammatical joint, not just a pause for breath. A long subject invites a breathing pause before the verb, and writers mistake that pause for a grammatical boundary. It isn't one. The next skill in this unit asks the same bracketing question in reverse: once you've found the boundary, decide whether it ever needs a comma, semicolon, colon, or dash, or whether, as here, the honest answer is nothing.