There’s No Choice but to Return for the Time Being

"Mom, that's too little. With this little money, I can only buy two plane tickets. Ying Ying is not young anymore. When she takes the bus or plane, she has to pay for the full fare. You didn't give me money for Ying Ying's ticket."

"I gave it to you. Didn't you say that the money I gave you is enough for two tickets? One for you, and one for Ying Ying. Doesn't that make two?" Why was it not enough?

"Then, how will I come back?" There was still one ticket missing!