学生的平均年龄是16岁。

The ___average age of the students is 16 years.

夏季，这里的平均温度大约是25°C。

In summer, the ___average temperature here is around 25°C.

这个地区的平均降雨量是每年500毫米。

The ___average rainfall in this region is 500 mm per year.