1、write off 引申：放棄、不管的意思
例：
we'd better write him off.(口語）
we'll never get the money back.I think we should write it off.
其他意思，參考金山詞霸
1）流利地寫下, 迅速寫出
She has written off an account of her trip.
她壹口氣把旅行見聞寫了下來。
2）損失掉, 排除
It may not be a bad thing that they write off their marriage before it begins.
他們斷絕了關系未結婚, 這可能並非壞事。
3）毀掉; 結束掉
They wrote the car off.
他們將那輛汽車報廢了。
The plane was completely written off and the pilot died.
飛機全毀, 飛行員身亡。
2、cross out 刪除、去掉的意思這個詞組沒有什麽引申含義，就是本身的詞義。
1）勾掉, 劃掉
He crossed out three wrong words.
他劃掉了三個錯字。
2）刪去，取消，抹掉
Cross the name of the dead person off the list！從名單上刪去已故人員的名字。