发热以夜间为甚，其病机是( )A．湿温内蕴 B．温病人营 C．阳明腑实 D．气虚

Learning curve theory emphasizes that in producing many goods, ______ .

A) cost decreases as production rates increase
B) average unit cost decreases as more units are produced
C) materials become cheaper when they are purchased in bulk
D) laborers become more productive because of technological advances

有一根长64厘米的木条，全部用做一个长方形的木框。木框的长与宽的比是9：7，这个木框的面积是（    ）平方厘米。

消除金属型材的不平、不直叫矫正。

短纤维纱是将天然的或合成的短纤维年成一股连续的纤维线、由这种线织成的滤布特点是颗粒截留性能好、同时可提供极佳的密封性能。