Evaporative cooling refers to the fact that a liquid absorbs heat during the process of evaporation into a gas, thereby reducing the surrounding temperature to achieve a cooling effect. The evaporative cooling effect refers to the value of a group in a social group composed of people with the same purpose or similar interests. The overall temperature is similar. When higher value members leave the community, the average value of the community itself will decrease. According to the above definition, which of the following is evaporative cooling effects? ['After the head of a hip-hop club of a college graduated and left school, the club did not get a better place in the hip-hop competition.', "A singer of a well-known pop music singing group died unexpectedly, and a large number of fans believe that the singer's departure caused the group's overall singing level to be greatly reduced.", "Some teachers of an educational institution left the institution to start their own education company, making the situation of the institution's competition in the market more severe.", 'The number of film review groups on a social networking site was small at the beginning and the quality of film reviews was high. Later, a large number of people joined this group to upload film reviews, which reduced the overall quality of film reviews here.']