题干
When I got to school, I realized I ______ my backpack at home.
A：left
B：had left
C：forgot
D：had forgotten
答案(点此获取答案解析）
B
When I got to school, I realized I ______ my backpack at home.
A：left
B：had left
C：forgot
D：had forgotten
的（ ）倍.
