英语语法分析

The invention provides natural pyrethrins pollen and the preparation method thereof.

本发明为天然除虫菊素花粉剂及制备方法。

Objective To observe the efficacy of pyrethrins aerosol against cockroaches by bioassay.

目的通过生物测试，观察天然除虫菊素杀虫气雾剂对蟑螂的药效。

Nearly 90% of exposures involved insecticides containing pyrethroids, pyrethrins or both.

将近90%的杀虫剂都含有除虫菊酯或者虫菊酯或者兼而有之。