题干
Mark Twain ______ school and began to work at the age of twelve.
A：left
B：leaves
C：will leave
D：leave
答案(点此获取答案解析）
A
Mark Twain ______ school and began to work at the age of twelve.
A：left
B：leaves
C：will leave
D：leave
，
，
，
，则
等于（ ）
