鸡舍内氨气允许浓度应不超过: A: 20 ppm B: 10 ppm C: 50 ppm

In the traditional Chinese calendric system, years are designated by _______ Heavenly Stems and _________ Earthly Branches. A: 12; 10 B: 10; 12 C: 10; 10 D: 12; 12

1 2 3 4 5 6 7 8 9 10

鸡舍内氨气允许浓度应不超过: A: 20 ppm B: 10 ppm C: 50 ppm

能产生臭鸡蛋味的硫化氢的最小浓度是多少（） A: 小于1 ppm B: 10 ppm C: 20 ppm D: 100 ppm

苯酚蒸气最大允许浓度（）PPm。 A: 2 B: 3 C: 5 D: 10

18038000646fdf7.png的CO相当于（ ）ppm A: 4 B: 6 C: 8 D: 10

180323c50206563.png的CO相当于（ ）ppm A: 4 B: 6 C: 8 D: 10

18036e3b8618c17.png的CO相当于（ ）ppm A: 4 B: 6 C: 8 D: 10

1803007eb9b3ade.png的CO相当于（ ）ppm A: 4 B: 6 C: 8 D: 10

1803d60cde507be.png的CO相当于（ ）ppm A: 4 B: 6 C: 8 D: 10

硫化氢浓度为1%，则表示（）ppm A: 10 B: 100 C: 1000 D: 10000

In the traditional Chinese calendric system, years are designated by _______ Heavenly Stems and _________ Earthly Branches. A: 12; 10 B: 10; 12 C: 10; 10 D: 12; 12

18038000646fdf7.png的CO相当于（）ppm A: 4 B: 6 C: 8 D: 10

180323c50206563.png的CO相当于（）ppm A: 4 B: 6 C: 8 D: 10

18036e3b8618c17.png的CO相当于（）ppm A: 4 B: 6 C: 8 D: 10

1803007eb9b3ade.png的CO相当于（）ppm A: 4 B: 6 C: 8 D: 10

1803d60cde507be.png的CO相当于（）ppm A: 4 B: 6 C: 8 D: 10

In the traditional Chinese calendric system, years are designated by _ Heavenly Stems and ___ Earthly Branches. A: 12; 10 B: 10; 12 C: 10; 10 D: 12; 12