查看原题
设集合 $M=\{x \in N \mid y=\lg (3-x)\}, N=\left\{y \mid y=2^x, x \in M\right\}$, 则
A. $M \subseteq N$     B. $N \subseteq M$     C. $M \cap N=\{0,1,2\}$     D. $M \cup N=\{0,1,2,4\}$         
不再提醒