Part of your question is in Polish; however, it can still be answered.
Answer:
<em><u>b) Write the sentences in the plural.</u></em>
2. Are there plants in your living rooms?
3. There are keys in those doors.
4. Are there toilets in these restaurants?
5. There aren't windows in these rooms.
<em><u>2 Circle the correct form. </u></em>
It's a very nice house. There's a large garden and there are some trees in the garden. I think they are apple trees. There's a living room with a big blue sofa. In the kitchen there aren't any shelves but there are some cupboards. They are quite old but the fridge and cooker are new. And the bathroom's fantastic. It isn't very big but there's a shower and a bath!
Explanation:
The plural is formed by adding <em>-s</em> to most regular nouns. Besides, verb forms, indefinite articles and demonstratives also change from singular to plural.
On the other hand, subjects pronouns are used to refer to a thing mentioned before, while <em>there is </em>and <em>there are</em> indicate existence.