jack rafter

例句：

1. 1. Thejack rafter is the tallest partof the ship.
   杰克桅杆是船的最高部分。
2. 2. He climbed up to the jackrafter and took a look around.
   他爬上去到杰克桅杆，四处看了看。
3. 3.The sailors were busy fixing thejack rafter after the storm.
   暴风雨过后，水手们忙着修理杰克桅杆。