- Who wrote this book?
- Who is painting the walls?
- Who will organize the event?
- Who has solved the problem?
- Who was building the bridge?
- Who had finished the report before the deadline?
- Who is going to prepare the presentation?
- Who discovers new species every year?
- Who was conducting the experiment?
- Who had been writing the article before the interruption?
- Who will be making the announcement?
- Who has been investigating the case for months?
- Who had repaired the machine by the time you arrived?
- Who is going to paint the fence?
- Who was making the cake when you called?
- Who will have completed the project by next week?
- Who has been cleaning the house all day?
- Who built the Great Wall of China?
- Who is writing the letter?
- Who had been planning the event for months?
answers
- Who was this book written by?
- Who are the walls being painted by?
- Who will the event be organized by?
- Who has the problem been solved by?
- Who was the bridge being built by?
- Who had the report been finished by before the deadline?
- Who is the presentation going to be prepared by?
- Who are new species discovered by every year?
- Who was the experiment being conducted by?
- Who had the article been written by before the interruption?
- Who will the announcement be made by?
- Who has the case been investigated by for months?
- Who had the machine been repaired by by the time you arrived?
- Who is the fence going to be painted by?
- Who was the cake being made by when you called?
- Who will the project have been completed by by next week?
- Who has the house been cleaned by all day?
- Who was the Great Wall of China built by?
- Who is the letter being written by?
- Who had the event been planned by for months?