美国科学家发明了一种除草剂。这种除草剂借助阳光的作用可以使杂草自行死亡,不会损害粮食作物,对于人类和其他动物,也没有什么危险。这种除草剂被称为“激光”除草剂,因为它是借助光发挥作用的。它的主要成份是一种常见的无害氨基酸,也称氨基甲糖酸,存在于所有的植物和动物体内。这种除草剂在黄昏之前进行喷洒,量不宜多,然后由植物加以吸收。经过测定表明,每英亩大约使用五分之一磅除草剂便能见效。在伊利诺州的大学,科学家进行的试验表明,芹菜、藜和马齿苋等有害杂草在使用这种除草剂以后便迅速死去。 American scientists invented a herbicide. This herbicide uses the sun’s rays to kill weeds on their own without harming food crops, and without any danger to humans and other animals. This herbicide is called a “laser” herbicide because it works with light. Its main ingredient is a common harmless amino acid, also known as carbamate, found in all plants and animals. This herbicide is sprayed before dusk, should not be much, and then be absorbed by plants. It has been determined that about one-fifth of a pound of herbicide per acre can be effective. In Illinois universities, tests conducted by scientists show that harmful weeds such as celery, quinoa and purslane die quickly after the herbicide is used.