On New Year's Eve, we went to the Town Hall, where a lot of people were gathered. In twenty minutes, the Town Hall clock would strike twelve but, at five to twelve, it stopped, seeming as if it refused to welcome the New Year. On learning that it was an accident, the crowd began to laugh and sing. What a bizarre evening! You would use "Twenty minutes later" to begin describing what happened twenty minutes later; here you are describing what was expected, not what happened. "Seems like it refused to welcome the New Year." is typical of speech, but not writing: it has no subject ("it seems") and 'like' should not be used with a verb, only a noun. 'getting' doesn't fit hear, you could use 'getting to know', but 'finding out' would be better. On learning.. the word order needed to be reversed - the learning came first, then they laughed afterwards. 'Eve' is only used in special contexts, such as the name of a festival. You would use it if you wrote in full 'what a bizarre New Year's Eve' Re. your question: - a lot of people gathered: focus is on the action of gathering. - a lot of people were gathered: focus is on the outcome of gathering, i.e. the fact that many people were already there.

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