叶的表皮和老茎的表皮上气体交换的结构,它们分别称为()。
A、气孔和皮孔
B、皮孔和气孔
C、皮孔和水孔
D、水孔和皮孔
参考答案:A
补写出下列名篇名句中的空缺部分。(只选5小题)
(1)耳得之而为声, ___________________,___________________,用之不竭……(苏轼《赤壁赋》)
(2)屈原曰:___________________ ,___________________,是以见放。 (《楚辞·渔父》)
(3)其为人也,___________________,___________________,不知老之将至云尔。 (《论语》)
(4)故___________________,___________________;不积小流,无以成江海。(荀子《劝学》)
(5)___________________。独上高楼,___________________。(晏殊《蝶恋花》)
(6)间关莺语花底滑, ___________________。___________________,凝绝不通声暂歇。(白居易《琵琶行》)
Production of mechanical foam by a portable in-line foam proportioner().
A.increases the size of foam bubbles formed
B.increases the rate of foam production
C.improves the extinguishing properties of foam
D.gives the nozzleman more freedom of movement,since it can be placed anywhere in the hose line