The average of 3, 8 and 10 is 7.

数字3、8、10的平均数是7。

I spend an average of about $200 a year on books.

我平均每年大约花200美元买书。

below / above average

低于/超过平均水平

the national average

全国平均水平

Scientists believe the world’s average temperature has risen by about 0.8℃ since 1900.

科学家认为自1900年以来，世界平均温度已经升高了约0.8℃。

The average number of electronic devices rose from four per household in 1992 to 13 in 2007.

平均每户家庭的电子设备数量从1992年的4件上升到了2007年的13件。

children of average intelligence

智力一般的儿童

He was in his late twenties and of average height.

他年近三十，中等个头。

Freddy was an average student, but not an average person.

弗雷迪是一名普通的学生，但却不是一个普通的人。