第28题: [填空题]The U.S. population of kids (grow)______since the 70s, and will remain at high levels through the’ 90s. 参考答案:has been growing 答案解析:[答案精解] 句意:70年代以来美国的小孩人口一直在增长,90年代仍然保持高水平。该题考查的是时态。根据句意作谓语,用完成进行时。
第29题: [单项选择]Absorbed in her work, she was totally ______ her surroundings. A. liable for B. separated by C. oblivious of D. concerned about 参考答案:C 答案解析:liable for对……负责;separated by被隔绝,被孤立;oblivious of遗忘的,忘却的;concerned about关心,挂念。她专注于她的工作完全忘了周围的一切,所以选C。