—Whose notebook is this?
—It ________ be Alan’s. It looks like his.
句意：——这是谁的笔记本？——它可能是艾伦的。看起来像他的。
考查情态动词表推测。must一定；can’t不可能；might可能；mustn’t表禁止。根据“It looks like his.”可知，笔记本看起来像是艾伦的，表不确定的推测，故用might。故选C。
—Whose notebook is this?
—It ________ be Alan’s. It looks like his.
Mary ________ go to London next year but she is not sure.
—I’m sorry I ________not get there on time. The traffic is heavy now.
—That’s OK. Take your time.
