______to the national park before, Sue was amazed to see the geyser.
A.Being not
B.Not having been
C.Have not been
D.Having not been

It is believed _______causes insomnia.
A.too much caffeine which
B.that too much caffeine
C.it in too much caffeine
D.too much caffeine that

(50)
A.systems
B.materials
C.sources
D.structures

(49)
A.do
B.make
C.get
D.come

_____ from Bill, all the students said they would go.
A.Except
B.Only
C.Apart
D.Separate

(47)
A.connecting
B.looking
C.searching
D.linking

The policeman explained to us ______get to the market.
A.how
B.how could
C.how we could
D.how could we

Not until a money several years old________to exhibit signs of independence from its mother.
A.beginning
B.does it begin
C.and begin
D.it begins

"Never say that again.______"A.won't you
B.do you
C.don't you
D.will you

There's someone at the door. ______it.
A.I’m answering
B.I answer
C.I’ll answer
D.I answered