
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
Four objects A, B, C, and D start moving from the same point in the same direction at the same time. Their distances $f_{i}(x)$ (i=1, 2, 3, 4) as functions of time $x$ ($x \geq 0$) are given by:
$$f_{1}(x)=2^{x}-1, \quad f_{2}(x)=x^{3}, \quad f_{3}(x)=x, \quad f_{4}(x)=\log_{2}(x+1)$$
The following conclusions are drawn:
① When $x>1$, A is in the front;
② When $x>1$, B is in the front;
③ When $0<x<1$, D is in the front, and when $x>1$, D is at the back;
④ C can never be in the front, nor can it be at the back;
⑤ If they keep moving, the one that will eventually be in the front is A.
Among these, the correct conclusions are \_\_\_\_\_\_ (Fill in the correct conclusion numbers, neither overfilling nor underfilling will be awarded points).

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