1. Given non-zero real numbers $a$ and $b$ satisfy
$$
|2 a-4|+|b+2|+\sqrt{(a-3) b^{2}}+4=2 a \text {. }
$$

then $a+b$ equals ( ).
(A) -1
(B) 0
(C) 1
(D) 2
- 1. C

From the given, we know $a \geqslant 3$, so the given equation is
$$
|b+2|+\sqrt{(a-3) b^{2}}=0 \Rightarrow a+b=1 \text {. }
$$