Question

--Have you found your book yet? --- No, I’m not sure where I________ it? A．leave B．had left

--Have you found your book yet? --- No, I’m not sure where I________ it? A．leave B．had left C．could have left D．was to leave.

Answer 1

C

本题考查时态。根据句意：——你还没有找到你的书？没有，我不确定我能够把它丢哪儿了。故用could have done本能够做，选C。