X线胶片的结构主要包括()
A.乳剂膜
B.保护膜
C.结合膜
D.片基
E.荧光体层
参考答案:A, B, C, D
I hear __________ boys in your school like playing football in their spare time, though others prefer basketball.
A.quite a lot
B.quite a few
C.quite a bit&n mso-bsp;
D.quite a little
热继电器的主双金属片与作为温度补偿元件的双金属片,其弯曲方向相反。