acquaintance

I say hello.

私はあいさつします

I say hello to an acquaintance.

私は知人にあいさつします

I say hello to an acquaintance at the exhibition hall.

私は展示場で知人にあいさつします

I say hello to an acquaintance at the exhibition hall on the day of the opening ceremony.

私は開幕式の日に展示場で知人にあいさつします

I say hello to an acquaintance at the exhibition hall with my colleague on the day of the opening ceremony.

私は同僚と開幕式の日に展示場で知人にあいさつします