Past perfect tense 10 предложении

1.I had done my homework by three o'clock 2.She had read the book by Friday 3.That student hadn't completed his degree work by the end of the year 4.I had arrived in Moscow by seven o'clock  5.She had found the key when I called 6.They bought the cars which we had shown them 7.When I came to work they had already completed the meeting  8.Marina had left by the 15th of June  9.When we called for Julia, she hadn’t yet got up 10.I had thought you knew about our problem  .