
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
In a box, there are 6 ballpoint pens, among which 4 are of first-class quality and 2 are of second-class quality. Two pens are drawn sequentially from the box. Calculate the probability of the following events:  
(1) Exactly one pen is of first-class quality;  
(2) At least one pen is of second-class quality.

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