胸锁乳突肌及斜方肌一侧肌力下降或肌肉萎缩提示受损神经是（）
A.迷走神经
B.面神经
C.副神经
D.舌咽神经
E.三叉神经
参考答案：C
对青少年骨骼发育有利的食物中，应含较多的（ ）
A．铁、铝和维生素C
B．铁、锌和维生素A
C．碘、铜和维生素B
D．钙、磷和维生素D
Assume that output increased from 1550 to 1850 units per day as a result of increasing labor from 200 to 210 workers. The marginal product of labor is closest to:（）
A. 1.55 units per day per worker.
B. 30 units per day per worker.
C. 1.25 units per day per worker.
