——There must be a dozen pens in this house but I can never find one when I need one.
——Keep looking. ______is sure to turn up.
A. One B. It C. That D. This
——There must be a dozen pens in this house but I can never find one when I need one.
——Keep looking. ______is sure to turn up.
A. One B. It C. That D. This
A
此处one特指上文提到的“the one I need”。