There are several bad effects that come from poor air-conditioning system.Firstly,poor air-conditioning system can make people lose their concentration.This is because the surrounding is not comfortable.So, they will get bore faster.In addition,the air is not fresh enough for our breathing system to support the brain.When the surrounding is warm,people will release smelly odour.So,the people especially student will be distracted by the smell.When the technical workers come to fix the air-conditioner, it will disturb the people who want to use the venue.So, it will make their life more difficult.In conclusion, the air-conditioner must always be in good condition to benefit the people.