---William, you ________ the car．

---Sorry．I didn’t see the red light．

1. A.
   should have stopped
2. B.
   couldn’t have stopped
3. C.
   must have stopped
4. D.
   needn’t have stopped

----- It was a red light, William. You ________ the car.

------- Sorry, I didn’t see it.

—It was a red light, William. You          the car.

—Sorry. I didn’t see it.

A．must stop                        B．should stop

C．must have stopped                  D．should have stopped

—It was a red light, William. You ____ the car.
—Sorry.  I didn’t see it.