— 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
Cars do cause people some health problems, in fact far more serious _____ than computers do.
A．one B．ones C．it D．those
