18.The newcomer went to the library the other day in search of ____________he could find about
Mark Twin.
A.wherever B.whatever C.whoever D.however
I woke up with ____________headache,yet by __________evening the pain had gone.
A.the;the B.the;an C.a;the D.a;an
Not until Mary reads her composition the second time ___________the spelling mistake.
A.did she notice B.she noticed C.does she notice D.she has noticed
-Look! Someone __________sofa.
-Well,it wasn`t me.I didn`t do it
A.is cleaning B.was cleaning C.has cleaned D.had cleaned
.I was about to get on the bus __________my wife phoned me to back home at once.
A.when B.while C.until D.after
We must do what we can to ____________the river ______________.
A. protect; against polluting B. stop; polluting
C. keep; being polluted D. prevent; from being polluted
