The teacher asked us to stand _____ a line before playing the game.
stand in a line 是固定搭配，意为“站成一队”，故所缺的介词是 in，故答案为选项B。
An _____ is something that you do,especially when this has an effect on what you feel or think.
本题考査名词辨析。
electricity 电；experience 经历；experiment试验。结合题干中的“就是你做的事情”以及“它对你的感受和想法有影响”可推断，符合题意的词是“经历”，故答案为选项B。