It had been raining before the party started, …

Step 1: Analyze the question This is a question tag. A question tag repeats the auxiliary (helping) verb of the main statement and reverses its polarity: a positive statement takes a negative tag, and a negative statement takes a positive tag.

Step 2: Identify the verb form in the statement "It had been raining before the party started."

This is the past perfect continuous tense: had + been + verb-ing.

• The first auxiliary verb is had.
• The statement is positive, so the tag must be negative.

Step 3: Build the tag Auxiliary (had) + not + pronoun (it) → hadn't it?

Step 4: Check the options

• A. isn't it? Wrong. The statement is not in the present simple of "be".
• B. wasn't it? Wrong. "Was" does not match "had been raining". The tag must use the first auxiliary, "had".
• C. hasn't it? Wrong. "Has" is present perfect, but the statement is in the past perfect.
• D. hadn't it? Correct. It matches the auxiliary "had" and reverses the polarity.

Answer: D

Tip: To form a question tag, find the first auxiliary verb in the statement and reuse it with the opposite polarity. For example:

• "She has gone, hasn't she?"
• "They had left, hadn't they?"
• "It had been raining, hadn't it?"

Don't be distracted by the "been" or the "-ing" word. Only the first auxiliary matters.