A．流速越大、压强越大
B．流速越大、压强越小
C．压强与流速无关
D．无法确定
答案：B
To me, cycling at ___ altitude of more than 4,000 meters was _____ unforgettable experience.
A．the; an
B．an; an
C．/; a
D．an; /
用于智齿冠周炎冲洗的过氧化氢溶液浓度是
A．1%～3%
B．0.1%～0.3%
C．0.3%～0.5%
D．0.25%～0.5%
E．5%～10%
