A:a more confusing
B:more confusing a
C:a most confusing
D:the most confusing
-- It's difficult for the village children to cross the river for school.
-- I think a bridge ________ over the river.
下列句子句式不同的一项是( )
次氯酸(HClO)具有杀菌消毒的作用,HClO中氯元素的化合价为( )
苯酚及其衍生物广泛存在于工业废水中,对环境有严重危害.小明同学准备依据图1操作步骤,从处理废水的活性污泥中分离筛选酚降解高效菌株.请回答下列问题: