say sth.about ,就.来说点.
talk about 中间没有词,谈论
再问： what did they ___about at the meeting? _something about the volleyball game.
再答： what did they talk about at the meeting? (they talked about) something about the... 或者相当于they said something about the volleyball game.
再问： -----what did they ___about at the meeting? -----something about the volleyball game 是用 say 还是用talk
