她低于平均身高，娇小且苗条。

She was of below average height, petite and slender.

《柯林斯英汉双解大词典》

这个月的降雨低于平均降雨量。

There has been below average rainfall this month.

《牛津词典》

相对贫困一般被认为是家庭收入水平低于平均家庭收入的特定比例。

Relative poverty is generally considered to be a household income level, which is below a given proportion of average family income.

youdao

OK, elements with low average valence electron energy, and here I'm saying below 11 electron volts, these are good electron donors.

平均价电子能都较低的元素，我是指那些低于11电子伏的，这些是很好的电子给体。

麻省理工公开课 - 固态化学导论课程节选