将炭粉和铁粉均匀混合,撒入内壁分别用氯化钠溶液和稀醋酸溶液润湿过的具支试管中,并按下图装置好仪器,观察下图,示意正确的是 [ ]
A.
B.
C.
D.
答案:B
正常雨水和酸雨的pH分别是 [ ]
A.5.6H5.6以下
B.7和5.6以下
C.7和7以上
D.5.6和7以下
Your ________ is so sweet, you will be a great singer in the future.
A.sound
B.noise
C.smile
D.voice