The air is pure , with neither pollution nor pollen .

空气是那么纯，没有污染物也没有花粉。

Plan workouts when pollen counts are low .

在花粉含量低的时候进行锻炼。

Pollen samples indicated forests were replaced by fields of cotton and corn .

花粉样本也表明森林被棉花地和玉米地所取代。

Pollen is usually blown to other trees and fertilizes their ovules .

花粉通常会被风吹到其它树上使其受精。

Also , seeds and pollen found in them can help reconstruct previous environments .

其中含有的种子和花粉还可以帮助重构先前的环境状况。