23 As soon as I got to the airport, I realized I______ my ID card at home.
A
had left
B
has left
C
would leave
D
will leave
关键词是I realized，此处是过去时，落下leave应该是在意识到之前，因此用过去完成时。故选A.
本题是语法知识题。本句意思是：我一到机场，我就意识到我的身份证忘在家里了。此处选A.
把握不准时态。