Answer: (Just a few:-)Adjective clauses:
1. The room <u>where the children sleep</u> is large. (replace 'there')
2. The mailman <u>who delivers our mail</u> is old. (replace 'he')
3. (Tricky) The table of which I fixed the broken leg* is an antique. (awkward but follows the "rule" not to use <u>that.)</u> (replace 'its.)
Better: The table with the broken leg which I fixed is an antique.
Noun clause section:
1. <u>Whoever is ready to work</u> will be welcome.
2. You may be surprised by <u>how much there is to be done.</u>
3. The grand prize will go to <u>whichever float has the best design and workmanship.</u>
Explanation:
The idea is to replace one word--usually a pronoun-- in the second sentence with a relative pronoun (They look like interrogative pronouns: who, which, where, when.)
Then rearrange the words of the second sentence to create an adjective clause and insert the clause after the noun it modifies in the first sentence.