Open the brackets, using the correct tense form. Explain the use of the tenses.
"For the simple reason that I (see) the dog at our door and I (hear) the bell which its master (ring). I wonder why Dr Mortimer (want) to see Mr Sherlock Holmes. Well, we soon (know). Come in," he (add), there (be) a knock at the door.

saw-heard-was ringing-wanted-know-added-wassaw,heard,wanted,added,was-Past Simple -констатация факта в прошломKnow-Present simple по согласованию временwas ringing-past continuous-действие в процессе