Conversation 3:

A:Hello，may I speak to John Edison？

B:Yes，speaking.

A:Hello，John，this is Mark Kent.I'm sorry but I have to cancel our lunch appointment tomorrow.

B:I'm sorry to hear that.

A:My boss sent me to Shanghai for an important negotiation tomorrow，and I won't be back until next month.

B:No problem.We can make it sometime next month，have a nice trip.

A:Thank you.