I.用所给动词的适当时态填空:
1. The clock _________ (strike) four as Mary ________ (reach) her flat. She _________ (light) a final cigarette and _______ (sit) at her dressing table, thinking of the party she _____ (leave) an hour before. She would have been home much earlier but she _______ (have) difficulty in finding a taxi at that later hour.