Kids often feel better in a happy family.
That's true. A happy family provides a loving _____for its children.( )
A.expressionB.environment
C.encouragementD.development
要得到函数的图象,只需要将函数的图象()
已知,则的值为()
若为虚数单位,则()
已知向量,如果向量与平行,则的值为()
已知集合,,则()