—Tom, Jane wanted you to call her.
—I’ll ____ in twenty minutes. Thank you.
| A．call on her | B．call her on | C．ring up her | D．ring her up |
I'm a singer is a program ______ is enjoyed by people of different ages.
| A．who | B．whom | C．that | D．what |
A friend is a person who knows what you are saying ______ you are not talking.
| A．because | B．until | C．unless | D．even if |
It is true that knowledge ______ rather than being taught.
| A．learns | B．learned |
| C．is learned | D．was learned |
Don't give up, Tom. You haven't realized ______ great progress you've made!
| A．what | B．what a | C．how | D．how a |
Grace has been a teacher for two years. She ______ in a school when I first met her.
| A．teaches | B．has taught | C．is teaching | D．was teaching |