指土壤土粒靠吸湿水外层剩余的分子引力从液态水中吸附一层极薄的水膜称为()
A.吸湿水
B.膜状水
C.毛管水
D.>重力水
参考答案:B
In that school, German is compulsory for all students, but English and French are_______.
A.special
B.regional
C.optional
D.original
某天然气大气式燃烧器的热负荷为41868kJ/h,若火孔热强度取6.5W/mm2,则燃烧器的火孔总面积约为()mm2。
A.1 826
B.1 857
C.1 938
D.1 905