18. _________ the library for hours without finding anything useful, I turned to my professor for help.
A: To search
B: Having searched
C: Have searched
D: Searching
A: To search
B: Having searched
C: Have searched
D: Searching
举一反三
- ( )the library for hours without finding anything useful,I turned to my professor for help.
- The police （） for the thief everywhere when he suddenly appeared in a theatre. A: search B: have searched C: were searching D: are searching
- The police have _____ the area for about two days, but so far have found nothing. A: search B: searched C: searching D: searcher
- It is most desirable that she _____ for the information by herself with a few clicks online. A: search B: searched C: have searched D: will search
- Jane has already （）the Internet A: search B: searching C: searches D: searched