A.越長(zhǎng)越好 B.<10s C.10-20s D.<30s
A.充氣量大 B.氣泡中應(yīng)有小氣泡和微細(xì)氣泡 C.礦物表面不易被水潤(rùn)濕 D.刮泡速度快,泡沫層面積大