________(7)
A.every
B.ones
C.each
D.by

________(6)
A.off
B.with
C.on
D.in

_______(46)
A.extinction
B.extinct
C.exist
D.existence

_______(48)
A.to drain
B.drainage
C.drain
D.draining

______(49)
A.survive
B.save
C.reduce
D.increase

_______(50)
A.remote
B.isolated
C.wilderness
D.desert

A.flame
B.hate
C.page
D.adventure

A.helped
B.liked
C.watched
D.hated

A.good
B.book
C.foot
D.food

There (be)............. no guests at all since I left.
A.has been
B.have been
C.were
D.are