sound off
phrasal verb with sound verb uk/saʊnd/ us/saʊnd/
informal
（尤指未经邀请）大发议论，言辞激烈地发表意见
to express your opinions forcefully, especially without being asked for them
He's always sounding off about how he thinks the country should be run. 他总是大发议论，表明自己对治理国家的看法。