Because she was a teacher... and he was going to be gone for a week= seven days.. so he gave her an apple for every day
OK what do you need help in
The only sentence here with an infinitive phrase is the first one, and the infinitive phrase there is 'to write'. You ask the question - What did Christa choose? in order to find the object of that sentence, and the answer is 'to write'.
2. What has Mary sold? (This is because her old car is bold in the sentence, which means that the question would be asking <em>what</em> was sold by Mary.)
3. Who is writing an email? (This is because Harriet is bold, which means that the question would be asking <em>who</em> was writing the email.)
4. Who like this book? (Joseph is bold, which means that the question is asking <em>who</em> likes the book.)
5. What does Joseph like? (this book is bold, meaning that the question is asking about <em>what </em>Joseph likes.)
6. What did Maya lose? (her ring is in bold, meaning that the question would be asking <em>what</em> Maya lost.)