Fill in the Blanks (Reading & Writing)

River cleanups organised by local volunteers have —removedremoveremovingremoval tonnes of plastic waste from waterways in the past decade. Teams typically —gathergatheringgatheredgathers along riverbanks at dawn, sorting recyclable material from debris too degraded to salvage. Environmental groups argue that such efforts, while valuable, cannot —replacereplacingreplacedreplacement the need for stricter regulation of upstream industrial discharge, since litter otherwise —accumulatesaccumulateaccumulatingaccumulated faster than volunteers can remove it.