1.Ofalltheeconomicallyimportanttrees, palmshavebeen ___.
A.thelaststudiedB.studytheleast
C.studylessandless
D.tostudytheless
2.Notonly ___ todeterminethedepthoftheoceanfloor, butitisalsousedtolocateoil.
A.touseseismologyB.isseismologyused
C.seismologyisused
D.usingseismology
3.It'shightimesomeone ___ himtostopbehavinglikeachild.
A.willtellB.told
C.tell
D.shouldtell
4.___ theEnglishexamination, IwouldhavegonetotheconcertlastSunday.
A.InspiteofB.Butfor
C.Becauseof
D.Asfor
5.Themorningclass ___ over, studentsrushedoutoftheclassroomforlunch.
A.wasB.is
C.havingbeen
D.being