Answer:

    PRINT "Enter the number of repeats"
    INPUT LIMIT

    IF LIMIT < 0 THEN
      PRINT "Number must be zero or greater"

    ELSE

      LET COUNT=1
  |   DO WHILE COUNT <= LIMIT
  | |   IF COUNT < LIMIT / 2 THEN
  | |     PRINT "Hello"
  | |   ELSE
  | |     PRINT "Mars"
  | |   END IF
  |
  |   LOOP
      PRINT "Done"

    END IF

    END

Matching the Outer IF

The DO must match the LOOP, so there was not much choice about the answer.

QUESTION 24:

Now match the IF in the statement:

    IF LIMIT < 0 THEN