在钢筋混凝土结构中,钢筋与混凝土之间之所以能共同工作的最主要条件,就是钢筋与混凝土的黏结作用。两者之间的黏结力由哪几部分组成?
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___ a new library___ in our school last year?
A. Was; built
B. Is; built
C. Does; build
Did; build
Look! A nice picture___ for our teacher.
A.is drawing
B. is being drawn
C. had been drawn
D. draws
The doctor___ for yet.
A. isn’t sent
B. hasn’t been sent
C. won’t be sent
D. wasn’t sent
The Great Wall___ all over the world.
A. knows
B. knew
C. was known
D. is known