Complete the following sentence by using the correct form of the verb with the…

Answer: is going to rain.

Explanation: Use the "be going to" form for a prediction based on present evidence. The cloudy sky is current evidence that supports predicting rain soon.

• Why "is going to rain" is correct: it expresses a future event predicted from current signs (the cloudy sky).

• Why "is likely rain" is wrong: it is not grammatical. Use "is likely to rain" or "it's likely that it will rain" instead.

• Why "would have rained" is wrong: this is a past conditional form referring to hypothetical past events, not a future prediction.

• Why "must have rained" is wrong: this expresses a deduction about something that already happened, not a forecast of future rain.

Tip: For near-future predictions based on what you can see or hear now, use "be going to" (e.g., "It's going to rain"). For general probability use "is likely to" or "it's likely that".