________ students in the classroom ______ twenty. The others are in the library.
A．The number of ; is B．A number of; are
C．The number of; are D．A number of ; is
— Do you believe that paper is made _______ wood?
—Yes, I do. And you can see that books are made________ paper.
A．from; from B．from; of
C．of; from D．of; of
______ is said that our math teacher often does volunteer work on weekends.
A. One B. This C. It D. That
I took the wrong train _______. I didn’t even know it until half an hour later .
A. by mistakes B.by mistake
C.with mistake D. with mistakes
The mobile phone has influenced people’s life a lot since it ________.
A. invents B. invented
C. is invented D. was invented
--- I have trouble _______ my new computer.
---Don’t worry. I’ll show you how _______it.
A. using; using B. to use; to use
C. using; to use D. to use; using
