Complete the texts with the past forms of the verbs in breckets.
AMAZING COPEN.
William Sidis was (be) born in New York in 1898. He____ (can) speak more than ten languages and when he ___ (be) eleven, he____ (be) already a student at Harvard University. He _____ (be) already a professor when he ____ (be) twenty. He ___ (be) amazing but, unfortunately, he ____ (not/be) a happy child.​