描述材料的光学性能指标，影响照明效果的重要因素是哪个？
参考答案：
反射系数，透射系数，吸收系数。影响照明效果的重要因素是反射系数。
In addition to the farming they ______ since the 1990s, the Smiths have started a small business.
A．have done
B．had been done
C．were doing
D．have been doing
影响CVP的病理因素包括()
A．房颤
B．血管升压素分泌升高
C．PEEP
D．心包填塞
E．右心衰竭
