lop something off
phrasal verb with lop verb uk/lɒp/ us/lɑːp/ -pp-
(CUT)
切断，砍断，削去
to cut something off in one quick movement
I'll need to lop off the lower branches of the tree. 我要砍掉这棵树上低矮的枝杈。
(REDUCE)
informal减（价）；缩短（时间）
to reduce a price or the amount of time taken to do something by a particular amount
He lopped eight seconds off the record. 他将这项纪录缩短了8秒钟。