—Can you tell me ______ Sally will play the piano?—Yes, at nine o’clock. I think.
Johan didn’t review(复习) the lesson, ___ he couldn’t answer the teacher’s question.
---- My mother is ill in hospital? ---- _________.
---- Do you know Jack well? ---- Certainly, we _________ friends since ten years ago.
The box is too heavy for me _________.
It _________ rain this afternoon, but I am not sure.