I wonder ____ it is because I haven't been able to be outdoors for so long ____ I have grown so crazy about everything to do with nature. I can well remember that there was a time ____ a deep blue sky, the song of the birds, moonlight and flowers could never have kept ____(myself) spellbound. That ____(change) since I was there. For example, one evening when it was so warm, I stayed awake ____ purpose until half past eleven in order ____(have) a good look at the moon by myself. But as the moon gave for too much light, I didn't dare open a window. Another time five months ago, I happened to be upstairs until the window had to ____(shut). The dark, rainy evening, the wind, the thundering clouds held me ____(entire) in their power; it was the first time in a year and a half that I ____(see) the night face to face.

未成年人在进行自我保护时，不得以自我保护为借口，损害国家的、社会的、集体的利益以及其他公民合法的自由和权利。这表明（    ）

①公民的权利和义务是统一的                         ②国家对未成年人的保护是虚假的

③未成年人很难对自己实行有效的保护         ④未成年人依法享有各种权利，同时也必须履行法律规定的义务

已知一个物体由X个相同的正方体堆成，它的主视图和左视图如图，那么X的最大值是（　　 ）

如图，在一个标准大气压下，某同学将冰块放入空易拉罐中并加入适量的盐，用筷子搅拌大约半分钟，测得易拉罐中冰与盐水混合物的温度低于0℃，实验时易拉罐的底部有白霜生成．对于这一实验和现象的分析，正确的是（  ）