get on to/onto something
phrasal verb with get verb uk/ɡet/ us/ɡet/ getting | got | got or gotten
(SUBJECT)
转而谈论，开始讨论（另一话题）
to start talking about a different subject
How did we get on to (the subject of) your grandmother's cat? 我们怎么说着说着就聊起你奶奶的猫（的事儿）来了？
(PERSON)
UK（为了让其帮忙而）与…联系，写信给
to speak or write to a person or organization because you want him, her, or it to help you in some way
Did you remember to get on to the plumber about the shower? 你记着给管子工联系让他来修淋浴器了吗？