
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 function $f(x) = e^x + x$, for three points A, B, and C on the curve $y = f(x)$, where the x-coordinates form an arithmetic sequence, consider the following judgments:  
① $\triangle ABC$ is always an obtuse triangle.  
② $\triangle ABC$ can be a right triangle.  
③ $\triangle ABC$ can be an isosceles triangle.  
④ $\triangle ABC$ cannot be an isosceles triangle. Among these judgments, the correct ones are.

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