"The duck likes cold water."
Translation:הברווז אוהב מים קרים.
So, as I understand מים קרים means that מים is a plural noun, isn't it? Or it's just an exception? Are there any other words of this kind?
Yes. Some words are set plurals, and some of them don't even have a singular form, such as מים. Other exceptions are: שמים, חיים, פנים (sky, life, face). This is actually a bit confusing for me because when I speak English I keep stopping myself saying "my face are" or "the sky are" or "life are".
Why are there two vavs in ברווז? There is only one shown on Google Translate, but Duolingo keeps correcting me when I spell it that way. How is it pronounced?
I don't know what you saw or if it was corrected: ברווז from Google translate app.
Fun fact, word Scottish Whisky in French and Hebrew is the same.... וויסקי , otherwise known as... Le Whiskey!