______the library for hours without finding anything useful, I turned to my professor for help.

admin2018-03-28 97

问题 ______the library for hours without finding anything useful, I turned to my professor for help.

选项 A、To search
B、Having searched
C、Have searched
D、Searching

答案B

解析考查现在分词的完成时。表示其动作在谓语动词的动作之前完成，作时间或原因状语，找资料是发生在寻求帮助之前，用having seacrched，故选B。

转载请注明原文地址:https://kaotiyun.com/show/kkaK777K

大学英语三级A级

相关试题推荐

随机试题

最新回复(0)