
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 $f(x)=\sin 2x+ \sqrt {3}(1-2\sin ^{2}x)$.  
(I) Find the intervals where $f(x)$ is decreasing;  
(II) When $x\in\left[- \dfrac {\pi}{6}, \dfrac {\pi}{6}\right]$, find the range of $f(x)$.

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