当三角板绕点C旋转到CD与OA垂直时(如图①)，易证：OD＋OE＝ $\sqrt{2}$ OC；

当三角板绕点C旋转到CD与OA不垂直时，即在图②，图③这两种情况下，上述结论是否仍然成立？若成立，请给予证明；若不成立，线段OD，OE，OC之间又有怎样的数量关系？请写出你的猜想，不需证明．

照样子，写词语。

①粉红粉红、____、____、____

②小心翼翼、____、____、____

   The aim of students who came to school is to study. But to study requires (需要) a right way, or you waste either the time or the money. The following are the ways of studying.
   The best time for reading is morning, because in the morning, the air is fresh and the mind is clear. For that reason, we can get good result.
   In studying we must have patience (耐心). If we have not known a text well, we must read it again. We should not read the next one till we have learned the first one.
   When we are studying, we must put our hearts into the book, or we can get nothing from the book while we are reading.
   We must always ask “whys”. If it is not well understood, write it down and ask our teachers or our parents, or friends. In any possible way, we must know it completely and what we've learned can be used well and made better.
   Though there are many ways for studying, yet the above mentioned will be quite enough if we can keep them in heart and do so.

用“ 、 ，45°”等数字填空：

①向酒精灯内添加酒精时，不能超过酒精灯容积的____;

②用试管夹夹持试管时，试管夹应夹持在距管口____处；

③给试管内液体加热时，液体体积应不超过试管容积的____；给试管加热时，使试管倾斜一定角度约____．