Then, the doctor pumps the rubber ball

does the comma go after ball or pumps or after then with a semi colin after ball

The comma goes after Then. I don't know what the rest of the sentence is.

the rest of the sentencer is to fill the cuff with air

In the sentence "Then, the doctor pumps the rubber ball," proper punctuation would be a comma after the word "then" and no semicolon. The comma is used to indicate a pause after "then," separating it from the main clause "the doctor pumps the rubber ball."

Here's how you can determine the correct punctuation in similar cases:

1. Identify the main clause: The main clause is the part of the sentence that contains a subject and a verb and can stand alone as a complete sentence. In this case, the main clause is "the doctor pumps the rubber ball."

2. Identify additional phrases or clauses: Any phrases or clauses that appear before or after the main clause are called dependent clauses or introductory phrases. In this case, "Then" is an introductory adverbial phrase.

3. Use appropriate punctuation: After an introductory adverbial phrase, like "Then," a comma is typically used to separate it from the main clause.

Therefore, the correct punctuation is: "Then, the doctor pumps the rubber ball."