I'm wondering, FranParis, about those weeds. You took thriving weed to be plural, I think. There's no doubt that we say things like the weeds in my garden; don't you think we can say the weed clogged the outlet pipe to mean the weed in general, and not a particular single weed? It's not like the fish in my pond. What I'm suggesting is that thriving weed needn't have plural force.You have to keep the "a". You could put "like thriving weeds" but it wouldn't sound right when talking about a single person.