The two sentences that use a noun clause are:
- Emily spent several days thinking about what she had to do in order to make a good grade.
- Why they didn’t return any of my phone calls or emails is the question I want answered.
In the first sentence, "what she had to do in order to make a good grade" is the noun clause. In the second sentence, "Why they didn’t return any of my phone calls or emails" is also a noun clause.