To convert the questions into passive form, we need to identify the main verb in the active form and then change it to the corresponding passive structure. Here's how each question can be rephrased:

1. A: *Was the pizza delivered on time?* (This is already in passive form.)

2. A: *Is Mike invited to Amy's birthday party?*
(Passive form of "Does Amy invite Mike to her birthday party?")

3. A: *Are these books sold in Japan?*
(Passive form of "Do they sell these books in Japan?")

4. A: *Was I surprised by the news?*
(Passive form of "Did the news surprise me?")

5. A: *Was this letter written by Sarah?*
(Passive form of "Did Sarah write this letter?")

Here’s the final presentation of the questions in passive form:

1. A: Was the pizza delivered on time?
2. A: Is Mike invited to Amy's birthday party?
3. A: Are these books sold in Japan?
4. A: Was I surprised by the news?
5. A: Was this letter written by Sarah?