A型题 测量荧光强度时，要在与人射光成直角的方向测量，这是因为
A. 只有在与入射光成直角的方向上才有荧光
B. 在成直角方向测量可以避免散射光的影响
C. 在成直角方向测量可避免透射光的影响
D. 荧光的强度比入射光强
E. 以上原因都不对
Barely ______ asleep when her father awakened her.
A. did she fall
B. she had fallen
C. had she fallen
D. she fell
She has a small machine for ______ coffee beans.
A. breaking
B. smashing
C. grinding
D. crushing
His mother died when he was five, his father never remarried, and by the time he was eight he （）in three different countries.
A. had lived
B. was lived
C. was living
D. will have lived
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