题目

   While attending a conference, I returned to my hotel room late one evening. The overhead light outside my door was burned out and I had  41   finding the keyhole. When I  42   to open the door, I 43   around the wall for a light switch. I found a plate where a switch was  44    installed... but no switch!    Not discouraged easily, I remembered   45   a lamp by the bed when I laid my luggage  46     in the day. I found the bed in the  47   and then the lamp, but when I switched it on, nothing  48    ! I thought that perhaps if I opened the curtains 某兴趣小组在探究“种子萌发的环境条件”中，以当年饱满的大豆种子为材料进行探究，方案如表，请分析回答：瓶号种子123410粒相同种子10粒相同种子10粒相同种子10粒相同种子环境条件不放水放适量水放适量水放过量水置于温暖处置于温暖处置于冰箱保鲜层置于温暖处（1）实验结果是：只有2号瓶的种子能够正常萌发。实验结果表明种子萌发需要的环境条件是_____、水分和充足的空气。（2）如果要证明“种子萌发需要充足的空气”，应选择_____号瓶和_____号瓶作为一组对照实验。而1号瓶和3号瓶不能构成一组对照实验，原因是该组实验出现了_____个实验变量。