631. I’m not ready.
632. I’m not reading.
633. She isn’t happy.
634. She isn’t shopping.
635. We aren’t helping him.
636. We aren’t with him.
637. The sun isn’t bright.
638. The sun isn’t shining.
639. The baby isn’t crying.
640. The man isn’t swimming.
641. Jerry isn’t listening to the radio.
642. The children aren’t looking at the picture.
643. I’m not using the computer.
644. The sportsmen aren’t running.
645. The man isn’t carrying a box.