average stream flow

例句：

1. 1. The average temperature in winter is around -5°C.
   冬天的平均温度大约是-5°C。
2. 2. He was an average student who never achieved anything remarkable.
   他是一位普通学生，从未取得过什么显著成就。
3. 3. The team's performance was average, which disappointed the coach.
   球队的表现平平，这让教练很失望。