题目

                     Creepy Unsolved Murders That Happened on Halloween Halloween is the one night of the year where being scared is supposed to be good fun. However, amid all the harmless activities like trick-or-treating, sometimes genuinely frightening and disturbing things can happen. October 31 has been the date of some horrific murders and unexplained disappearances, which are far more terrifying than any ghosts, goblins, or witches. Because they happened to take place on Halloween, the following mysteries have an extra aura of creepiness to them, and they rem设NA为阿伏伽德罗常数，下列叙述正确的是                    （     ）A．28gC2H4所含共用电子对数目为4NA B．1L0．1mol·L-1乙酸溶液中H+数为0．1NA C．1mol甲烷分子所含质子数为10NA D．标准状况下，22．4L乙醇的分子数为NA