倾斜视线在水平视线的上方，则该垂直角（）
A.称为仰角，角值为负
B.称为仰角，角值为正
C.称为俯角，角值为负
D.称为俯角，角值为正
参考答案：B
Tom's mother kept telling him that he should work harder, but ______ didn't help. [ ]
A. he
B. which
C. she
D. it
能引起听觉的最小声强值称为（）
A.听觉级
B.声强级
C.响度
D.痛阈
E.听阈
