| The texture of the soil depends on the
relative amounts of different-sized particles that combine to make up the soil.
These particles can be as large as stone and gravel or as small as
clay. A typical clay soil is composed of approximately 60 percent actual clay, 20 percent silt, and 20 percent sand. The particles in a sandy soil are so fine that it tends to be compact and interferes with the oxygen supply for plant roots. Water has trouble entering this impervious soil, and runoff is very common during rainfalls. A typical light sandy soil is composed of approximately 70 percent sand, 20 percent silt, and 10 percent clay. The particles in a sandy soil are comparatively large, permitting water to enter the soil and to pass through it so quickly that it often carries nutrients with it and dries out very rapidly. The texture of sandy soils is genera A. its color B. the texture of its surface C. the size of the soil particles D. the number of nutrients present [单选题]机床照明、移动行灯等设备,使用的安全电压为()。
A.9.V B.12.V C.24.V D.36.V [单选题]测量低压熔断器和水平排列低压母线电流时，测量前应将各相熔断器和母线用（）加以包护隔离，以免引起相间短路，同时应注意不得触及其他带电部分。
A.金属材料 B.绝缘材料 C.棉麻材料 D.任意材料 [简答题]防止电气误操作(五防)的具体内容是什么?
[判断题]“TTT”计算方法是适合于所有冷冻食品推测其品质变化的有效方法。（）
[单项选择]关于高压蒸气灭菌下列哪项是错误的
A. 需要灭菌的包裹不应过大，一般应小于40×30×30 B. 放入灭菌器内的包裹不应排得太密，以免影响灭菌效果 C. 易燃及易爆炸物品禁用高压蒸气灭菌法 D. 用于金属器械、玻璃等物品的灭菌 E. 不宜用于瓶装液体灭菌 [单选题]液氯泄漏事故进入事故现场的救援人员必须佩戴隔绝式呼吸器,进入内部执行关阀堵漏任务的救援人员要按()防护标准加强个人防护。(难)
A.一级 B.二级 C.三级 D.特级 [判断题]某年某月某日,龙某在井下1203工作面作业时,擅自开动绞车,使下放的两节重车撞到停在空车道上的车斗,将掘进区爆破工庄某挤死,属于重大责任事故罪。( )
A.正确 B.错误 [单选题]在纵向坡度为5‰的坡段上两点，两点之间水平距离为2000m，那么两点之间高差为（ ）。
A.10000mm B.1000mm C.100mm D.10mm 我来回答: 提交
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