答案:C
登山时,将喝空的矿泉水瓶拧紧瓶盖。下山后瓶子变瘪,瓶内的气体分子
A.体积变小
B.个数变少
C.间隙变小
D.质量变少.
______ my little brother is a child , he knows a lot.
A.Even
B.If
C.Even though
D.Until