Поставить past simple или past perfect4. it (to be) nine o’clock and we (to come) to her room two hours before, as we (to do) often on those winter evenings.15. talking to him (to be) very easy; just like talking to someone you (to know) all your life. 16. when he (to come back) to his seat his manner (to change). he (to be) gentle and kindly. 17. george (to make) no answer, and we (to find) that he (to be asleep) for some time.

4. It was nine o’clock and we had come to her room two hours before, as we  often did on those winter evenings.

15. Talking to him was very easy; just like talking to someone you had known all your life.  

16. When he  came back to his seat his manner had changed. He was gentle and kind.  

17. George made no answer, and we found that he had been  asleep for some time.

Объяснение:

4. It WAS nine o’clock and we HAD COME to her room two hours before, as we often DID on those winter evenings.

15. Talking to him WAS very easy; just like talking to someone you HAD KNOWN all your life.  

16. When he CAME back to his seat his manner HAD CHANGED. He WAS gentle and kindly.  

17. George MADE no answer, and we FOUND that he HAD BEEN asleep for some time.