Final answer:
The writer should ask whether rewording a sentence beginning with 'it is' adds clarity.
Step-by-step explanation:
The writer should ask the question 'Does it add clarity?' when deciding whether to reword a sentence that begins with 'it is'.
Starting a sentence with 'it is' can sometimes make the sentence unclear or vague.
By rewording the sentence, the writer can ensure that the meaning is clear and easy to understand.