一条小路上共栽有10棵树（两端各有一棵），这些树把小路分成了（ ）段。
9
I have five picture books. And my mother buys two story books for me. How many books do I have? [ ]
A. five
B. two
C. ten
D. seven
往复泵由哪些零部件构成？往复泵有哪些独特之处？
