衡量磨损特性的主要参数是磨损率,通常可采用以下三种磨损率:
参考答案:
(1)、线性磨损率:
(2)、体积磨损率:
(3)、重量磨损率:
阅读理解
Dear Mom,
I need some things for school. Can you bring them to my school? I need a notebook, two pencils, an
eraser and ruler. I need my CDs and video tape, too. The CDs are on the desk and the video tape is in
the bookcase.
Thanks.
Jim
Dear Jane,
Your brother needs some things for school. They're in the red bag. He needs his CDs and video tape,
too. The CDs are on the desk. The video tape in the drawer of his bed. It isn't in the bookcase. Please
take them to his schooL
Thanks,
Mom
1. Jane is Jim's ______.
A. cousin
B. daughter
C. sister
2. Jim needs ______.
A. a notebook and a red bag
B. an eraser, a ruler and a bag
C. two pencils and an eraser
3. _________are mentioned(提到) in the notes.
A. Two boys
B. A boy and a girl
C. Two girls
4. ______takes the things to school.
A. Jane
B. Jim
C. Jane's friend
5. The video tape is_______.
A. on the desk
B. in the bookcase
C. in the drawer
I wonder if this is the computer you want______ .
A.to have repaired
B.to have it repaired
C.it to be repaired
D.to repair it