
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given the universal set $U=\mathbb{R}$, $A=\{x|\log_{2}(3-x) \leq 2\}$, $B=\left\{x\middle| \frac{a}{x+2} \geq 1, a \in \mathbb{R}\right\}$  
(Ⅰ) Find the sets A and B;  
(Ⅱ) If $(C_{U}A) \cup B = C_{U}A$, find the range of the real number $a$.

Present the answer in LaTex format: \boxed{Your answer}
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