.
—Who______ it be that is knocking at the door?
—It ______ be Father, but I’m not sure.
| A．can; must | B．can; may | C．must; can | D．may; must |
--- Do you want a lift home?
--- It’s very kind of you , but I have to work late in the office . I over slept this morning because my alarm clock _________ .
| A．doesn’t go off | B．won’t go off | C．wasn’t going off | D．didn’t go off |
--- How far can you run without stopping ?
--- ______________ . I’ve never tried.
| A．Don’t mention it. | B．That’s all right. | C．I have no idea. | D．Go ahead. |
The traffic on the main streets has a longer green signal than ______ on the small ones.
| A．one | B． this | C． that | D．it |
That is the only way we can imagine ______ the overuse of water in students’ bathrooms.
| A．reducing | B．to reduce | C．reduced | D． reduce |
What are you doing out of bed ? You’re _______ to be asleep.
| A．supposed | B．known | C． thought | D． considered |