将下列词语分别填入句子中: flourish,crack,ignorant,indifferent,personnel,investigate,inhabitant 1. American Indians were the earliest ______s of America. 2. Rock and roll ______ed in the 1950s in the West. 3. I was so excited to see snow that I was ______ to the cold. 4. Her first job was in ______. 5. In cold weather, boiling water can _____ the glass. 6. People don't like to ask questions for fear of appearing _______. 7. Sherlock Holmes ______d many cases by following the footprints left at the scene of the crime.