设m、n是两条不同的直线，α、β、γ是三个不同的平面．给出下列四个命题：

①若m⊂α，α∥β，则m∥β

②若m、n⊂α，m∥β，n∥β，则α∥β

③若m⊥α，m⊥β，n⊥α，则n⊥β

④若α⊥γ，β⊥γ，m⊥α，则m⊥β

其中，正确命题的个数是（　　）

A．1

B．2

C．3

D．4

Being a parent is not always easy, and being the parent of a child with special needs often carries with

_______ extra stress.[ ]

A. it              

B. them            

C. one            

D. him