简述跳汰选煤优点。

当量摩擦系数f与（）和（）有关。

下列选项中不属于选择集编辑修改器的是哪个？（）

A、Edit Patch

B、Mesh Select

C、Loft

D、Edit Mesh

The process of gaining or losing weight can be explained by comparing your body to your car. Both run (51) fuel, food for your body and gasoline for your car. Both (52) that fuel, first into heat, then energy, some of (53) is used to do work, and some emitted as waste. And (54) your car uses more energy when the engine is racing than when it is idling, (55) does your body use more energy when you are working hard than (56) you are resting.

For the purpose of this comparison, (57) , there is one significant difference between them. Your car cannot store fuel by turning it into (58) else; all gasoline not (59) remains as gasoline. But your body stores (60) energy as fat. When the gas tank is completely empty, the car won’t run; but your body can burn fat to provide more energy.

54().

A. whereas

B. although

C. just because

D. just as

下列选项中的哪个组合是关于行政行为确定力的正确理解( )　　 ①相对人不得任意擅自改变行政行为；　　 ②行政主体非经法定程序不得任意改变或撤销行政行为；　　 ③相对人必须遵守和实际履行行政行为规定的义务；　　 ④行政行为在行政复议或行政诉讼期间不停止执行。

A．①②

B．②③④

C．③④

D．①②③④

丛书编委会由15人组成，该编委会名单一般应放在（）上。

A.版权页

B.主书名页正面

C.主书页背面

D.附书名页