单向双向：某些产品的手续费只在开仓时收取，有些则在开仓和平仓时都收取； The Sensitivities strategy [two] entails 1st calculating solution sensitivities often called the Greeks due to common practice of symbolizing the sensitivities applying Greek letters. On ne change rien à ce qui est en train de se passer, mais on modifie seulement son sens. En PNL, on distingue trois sorts Successfully Submitted (Awaiting Approval)