若把代数式$x^2-4x+2$化为${\left(x-m\right)}^2+k$的形式，其中m、k为常数，则k+m=____ 

    One day three Frenchmen who did not know English very well were talking about the English language.
The first Frenchman said, ‘I heard someone shout ‘look out’ ,I put my head out of a window and a basin of water fell on me. It seems that ‘look out’ may mean ‘don't look out!’
    The second one followed, ‘ I was once on a ship and heard the captain（船长） shout, ‘All hands on the deck(甲板)’ I put my hands on the deck and someone trod(踩)on them.’
    The third one told his friends his experience too, ‘One early morning I called on my English friend and the maid(女佣) said, ‘He is not up yet, come back in half an hour.’ When I went again for him, she said, ‘He’s not down yet.’I said, ‘If he’s not up and he is not down, where is he then?    What a strange language it is!’

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                                                                                    【甲】
      ⑴余幼时即嗜学。家贫，无从致书以观，每假借于藏书之家，手自笔录，计日以还。天大寒，砚冰坚，手指不可屈伸，弗之怠。录毕，走送之，不敢稍逾约。……
      ⑵今诸生学于太学，县官日有禀销之供，父母岁有裘葛之遗，无冻馁之患矣；坐大厦之下而诵《诗》《书》，无奔走之劳矣；有司业、博士为之师，未有问而不告，求而不得者也；凡所宜有之书皆集于此，不必若余之手录，假诸人而后见也。其业有不精，德有不成者，非天质之卑，则心不若余之专耳，岂他人之过哉？……
      ⑶自谓少时用心于学甚劳，是可谓善学者矣！其将归见其亲也，余故道为学之难以告之。
                                                                                                                                                      ——（宋濂《送东阳马生序》节选）
                                                                                     【乙】
      临川之城东，有地隐然而高，以临于溪，曰新城。新城之上，有池洼然而方以长，曰王羲之之墨池者。荀伯子《临川记》云也。羲之尝慕张芝，临池学书，池水尽黑，此为其故迹，岂信然邪?方羲之之不可强①以仕，而尝极东方，出沧海，以娱其意于山水之间。岂其徜徉肆恣②，而又尝自休于此邪？则其所能，盖亦以精力自致者，非天成也。然后世未有能及者，岂其学不如彼邪？则学固岂可以少哉！况欲深造道德者邪？
                                                                                                                                                              ——（曾巩《墨池记》节选）
【注释】①强：勉强   ②徜徉（chángyáng）肆恣：纵情遨游。