In paragraph 2 of Common Sense, the allusion to the events of April 19 supports Paine's argument by reminding readers that

negotiations have been made, and fighting has begun

Explanation:

in paragraph 2 of common sense, i have selected a few important sentences that can help get your answer.

firstly, the events of april 19 that they were referring to was the battle of lexington and concord. so what we are looking for are things that may have anything to do with this event, and what they remind the reader. part of the last sentence says: "they have an undoubted privilege to inquire into the pretensions of both, and equally to reject the usurpation of either" in other words, they (british) have the privelage to look into, or ask about, the claims of both, (american and british), and equally to reject the *place of someone illegally of either. he also references to the "violence" that has begun, and the entire "common sense" is advocating independence from great Britain. therefore the "allusion" (an expression designed to call something to mind without mentioning it explicitly; an indirect or passing reference) is that there is already fighting/violence and there have already been negotiations that have not worked.

yóu can speak tó no one, replíed the kní

meet you at the corner