21. When I arrived, Bryan took me to see the house_ I would be staying.
A. what B. when C. where D. which
22.I got to the office earlier that day, the 7:30 train from Paddington
A. caught B. to have caught C. to catch D. having caught
23. It was only after he had read the papers Mr. Gross realized the task before him was extremely difficult to complete.
A. when B. that C. which D. what
