0518 I got a flat tire

I rode my bicycle to mess hall yesterday evening.All of a sudden,I felt something wrong with the tire.It was getting more and more difficult for me to ride it.Finally I arrived at mess hall and took a look at the tire.Out of my surprise,I got a flat tire.It was my first time to deal with such an accident.
Last time my fiance and I wanted to ride bicycles,but there was only one bicycle,which was belonged to my fiance's sister in my house.It was a little folding bicycle and it's maximum endurance was 80 kilograms.We had no choice but to ride it.My fiance's weight was 92 kilograms and mine was 62 kilograms.Our weight was  twice as much as it's endurance.Though it was broken after we rode it,we did not got a flat tire.Then we put the bicycle back secretly as if nothing happened.The very next day my fiance's sister had a date with her boy friend.She rode the bicycle and found it was broken.When she knew that we both rode the bicycle which led to it's damage,she was like a bear with a sore head.The repair fee was too high.As a result,she had no choice but to give it up.
I do not know whether the repair will cost me lots of money or not.The bicycle was a gift from my sister,though it cost only 2800 dollars.It is a symbol of my sister's love.At short,I had to spend time and money repairing it this weekend.