When______ is not known.
A.it was invented the wheel
B.the wheel was invented
C.the invention of the wheel
D.was the wheel invented

They asked me a lot of questions, ______I couldn’t answer.
A.all of which
B.that
C.all of whom
D.who

This one is prettier, but it costs ______as the other one.
A.twice as many
B.as many
C.twice as much
D.so much

______electricity you use,_____ your bill will be.
A.The most - the higher
B.The more - the high
C.More - higher
D.The more - the higher

On September 9, 1850, California was admitted to the Union______
A.being thirty-first state
B.as the thirty-first state
C.for the thirty-first state
D.the thirty-first state

Relative humidity is the amount of water vapor the air contains at a certaintemperature______ with the amount it could hold at that temperature.
A.to compare
B.compared
C.comparing
D.compares

“You missed a good chance in your career." “Yes, I ______that job when Mr. Johnson offered.”
A.shall take
B.shall have taken
C.should take
D.should have taken

A.collective
B.climatic
C.abundant
D.regional

A.originate
B.evacuate
C.sanitary
D.certificate

Tony’s boss gave him permission to take two days off.
A.Tony’s boss left the office for two days.
B.Tony quit his job after two days.
C.Tony took two days off from work.
D.Tony's boss agreed to take off for two days.