Question

Look at those dark clouds. When class ( be ) over, it ( rain, probably )

Answer 1

When class will be over, it probably rains.

Answer 2

It looks like there are dark clouds in the sky, indicating that it will probably rain when class is over. This suggests that there may be precipitation in the near future. It's always a good idea to be prepared for rain by having an umbrella or raincoat handy. Keep an eye on the weather and be ready for any changes.