The pollution were terrible when the factory dumped its waste into the river.A B C D 改错

The pollution were terrible when the factory dumped its waste into the river.A B C D 改错
The pollution were terrible when the factory dumped its waste into the river.A B C D 改错

The pollution were terrible when the factory dumped its waste into the river.A B C D 改错
were->was
pollution不可数,做三单

were改为was

were ----was