William J. Sidis, was born in 1898. （1） father was an American psychiatrist. At the age of six months, William knew the English alphabet; he could read and write when he was two. When he was eight years （2） , young Sidis had completed both elementary and high school. At the age of nine, William entered Harvard University.
As a（3）at Harvard, Sidis displayed phenomenal knowledge in the field of mathematics, often amazing his professors. He graduated with honors （4）the age of 16 and became a full professor of mathematics at the university at 19.
The story of William J. Sidis， unfortunately does not end happily. This brilliant ex-genius died a lonely death in 1943 in a hotel room （5） New York.
3、______

A.student

B.at

C.in

D.dold

E.eHis