jumper是什么意思解释一下

　　He's a high-jumper.

　　他是一位跳高的.运动员。

　　The jumper from the Round Tower worked for him.

　　圆塔上的跳塔者，为他工作。

　　His clothes were dark and he wore a woolly jumper.

　　他的外套是暗色的的，穿了一件羊毛套衫。

　　Who has a lucky red jumper or something like that?

　　谁有一个幸运兔或者之类的东西？

　　The jumper-wearing Mr Marchionne is not given to self-doubt.

　　身穿套头衫的马尔基翁内不喜欢自我怀疑。