Вставьте, где возможно, Past Perfect. В остальных случая использовать Past simple.
Chris Haas, 15, 1 (invent) the Hands-On Basketball as a school project when he 2 (be) nine. The idea 3 (be) to make an invention to help people do something better, he remembers. Chriss father 4 (be) basketball coach for many years before he 5 (retire). I (know) how to shoot properly because my father 7 (teach) me, Chris says, 'so I 8 (paint) hands on a basketball to show the other players how to hold it.' No one 9 (think) of this before, and Chris 10 (sell) his idea to a big company. He 11 (not expect) to make a lot of money, but last year he 12 (earn) $50,000 from his invention.