One's a spineless, poisonous blob. The other is a form of sea life.
or
Because he wanted to be on time.
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I said, "I've been on telly but I'm no Dean Martin".
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If at first you don't succeed, cry and cry again!
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When it's going cheep!
Did you hear the one about the crow and the telephone pole?
He wanted to make a long distance caw.
or