touch on/upon something
phrasal verb with touch verb uk/tʌtʃ/ us/tʌtʃ/
（说话或写作时）简略提到，触及
to mention a subject quickly when speaking or writing about another subject
The talk was about educational opportunities for adults, and the speaker also touched upon sources of finance. 该报告谈的是成人的教育机会，报告人也提到了资金来源问题。