— Who _____ be phoning us at this time of night?
— It might be your sister.
| A．might | B．can | C．dare | D．must |
— You have helped me a lot. I can’t thank you enough.
—______.
| A．Be my guest. | B．That’s right. | C．I don’t think so. | D．Think nothing of it. |
I didn't realize my mother loves me so such until I received her gift for my 18th birthday, a diary______ the process of my growth．
| A．recorded | B．to record | C．recording | D．having recorded |
_____ the city’s public school system should be open to the children of migrant workers has become the focus of discussion.
| A．That | B．What | C．Whether | D．If |
—You may find the key to the math problem on page 107．
—Ah, it's so simple. I wonder why I _____ of that．
| A．hadn’t thought | B．haven't thought | C．didn't think | D．wasn't thinking |