The physics teacher once said that we first _____the lightning followed by thunders because light ______ faster than sound.
| A．see; traveled | B．saw; traveled |
| C．saw; travels | D．see; travels |
Bob ________ with us together since he came to our school.
| A．have worked | B．has worked | C．worked | D．will work |
When I came into the teacher’s office, he ________ on the phone.
| A．was speaking | B．spoke | C．had been speaking | D．had spoken |
Tony decided to study abroad _______ he knew he would meet many difficulties.
| A．as if | B．because | C．unless | D．even if |
--- We want to sit at the table near the window.
--- I am sorry, but it _______ already.
| A．took | B．takes | C．has been taken | D．is taking |
In some parts of the world, tea _______ with milk and sugar.
| A．is serving | B．is served | C．serves | D．served |