这道题sell the stock forward 不属于removal of all market risk嘛?另外sell forward 不算是题目里说的remove all market risk吗?那为什么答案里把total return swap和forward conversion with options归于removal of all market risk呢?答案说short against the box会要立刻交税怎么理解?sell the stock forward 和collar能把sale push into next year是啥意思?