题干
John started ________ on his Maths homework as soon as he got home.
A：to work
B：work
C：worked
D：works
答案(点此获取答案解析）
A
John started ________ on his Maths homework as soon as he got home.
A：to work
B：work
C：worked
D：works
的有理化因式是（ ）.