Our class _______ forty-five students, in other words, forty-five students ______ our class.
A.G→Q+NaCl
B.Q+H2O→X+H2↑
C.Y+NaOH→G+Q+HO
D.Z+NaOH→Q+X+H2O
判断氯的化合价由低到高的排列顺序( )
据中央电视台报道,阳朔农村老太太徐秀珍,年近60岁,会说英、德、法等近10种外语,被外国游客亲切地称为“月亮妈妈”。此事反映出旅游活动的作用是( )