A:KNO3
B:H2SO4
C:NaCl
D:蔗糖
—The teacher lost her temper because Jack was late again today.
—No wonder I saw Jack was crying just now.
李华的家在马路边,人来车往的噪声严重影响了他在家学习,请你想办法来帮助李华减弱干扰他的噪声(至少2个具体办法)。