Two. One to assume the ladder and one to change the bulb.
A': None. If the government would just leave it alone, it would screw itself in.
or
Do you want to grab a bite?
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One minds the train, one trains the mind.
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Only one. But he'll leave a big puddle of spit on the floor underneath him.
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Only one, but it may take upwards of five years for him to get it done.
or