1. With the development of economy，our income has increased ________ 10% in less than a year.
A. for B. by
C. on D. at
【答案】B
【解析】
考查介词。句意：随着经济的发展，我们的收入一年内增加了10%。increase by 表示“增加了多少”。故选B。
2. The professor could tell by the _________look in Mars's eyes that she didn’t understand a single word of his lecture.
A. cold B. blank
C. fresh D. innocent
【答案】D
【解析】
【详解】考查形容词辨析。句意：从Mari茫然的眼神中，教授可以看出她一点也没有听懂讲座的内容。A. cold冷的，冷淡的，无情的；B. blank空白的，茫然的，无表情的；C. fresh新的，新鲜的，淡的；D. innocent无辜的，清白的，天真的，头脑简单的。根据she didn’t understand a single word of his lecture.可知，这里是“茫然”的意思，故选D。
