However , the heavy bell of night , was still ringing the war , immature ideal , unable to tidy up an era , until you disappeared and hid agilely , the land was still full of corpses .
If we want to learn mathematical analysis well , above all we must fully understand and agilely utilize the mathematical concepts in it . Meanwhile , if one wants to master all these concepts , one should master not only the positive side of the concepts but also the negative side of them .