YOU SAID:

i went to a tea party in Boston then the assassins arrived

INTO JAPANESE

私はボストンのお茶会に行った後、暗殺者が到着しました

BACK INTO ENGLISH

I went to a tea party in Boston and then the assassin arrived

INTO JAPANESE

私はボストンのお茶会に行き、その後、暗殺者が到着しました

BACK INTO ENGLISH

I went to a tea party in Boston and then the assassin arrived