一、单项填空
1．—Mom，I lost ______ diamond ring you bought as my birthday present.
—I’ll keep______ eye on it when I clean your bedroom.
A．a；an B．the；an
C．the；the D．a；the
解析：第一个空特指“你买给我做生日礼物的那个”，因此用定冠词the；第二个空考查固定搭配keep an eye on“留意，密切注视”。
答案：B
2．It’s warned by scientists that polar bears will become extinct this century，which will be a loss for mankind that no amount of money could ______.
A．stand up to B．make up for
C．come up with D．put up with
解析：考查动词短语辨析。make up for“补偿，弥补”；stand up to“经得起，勇敢地面对”；come up with“赶上，提出”；put up w ith“容忍，忍受”。句意：科学家们警告说北极熊的灭绝将会是人类的损失，这种损失是多少金钱都弥补不了的。
答案：B
