The opuntia cactus are spread like a weed, killing off thousands of acres of grassland.

这种仙人掌像杂草一样疯狂生长，数千英亩的草地被毁。

Some weeds are strong enough to resist weed killing products, also known as herbicides.

有些杂草的强度足以抵抗除草剂， 也称为除草剂。