Pippa

And it's important to say that they only eat what they can identify with 100% certainty, sticking to the rule, if in doubt, leave it out.

I'm going to say if it's dangerous, maybe it's red.

Roshana's mother-in-law is a horticulturalist, a person who studies or grows plants such as flowers, fruits and vegetables.

She has a deep knowledge of the wild plants growing in nature.

A deep knowledge means a thorough understanding of a subject gained from experience and study, not just knowing the basic facts.

And of course, Roshana only eats plants that she can positively identify.

Plants that she knows 110% are safe to eat.

Here the idiom 110% means Roshana is completely sure, she has no doubt.

And that's important as the consequences of eating poisonous plants are serious, sickness or even death.

Emily thinks there's a stigma around mushrooms.

A stigma is a negative belief about something which is not necessarily true or fair.

In fact, many plants are just as poisonous as mushrooms.

And the best way of doing that is learning the difference between what's safe to eat and what's not.

Speaking of which, what was the answer to your question, Beth?

If you have a deep knowledge of a subject, you have a thorough understanding of it gained from experience and study.

If you're 110% sure about something, you're absolutely certain you have no doubt.

A stigma is an unfair negative belief about something.

And finally, to exercise caution is a more formal way of saying to be careful, something you should definitely remember if you go wild foraging yourself.

Once again, our six minutes are up.

If you enjoyed this episode, you'll find a quiz and worksheet to practice the vocabulary on our website, bbclearningenglish.com.