You ______be tired after working for eight hours without ______ a rest.

He used to _______ in a village, but now he has been used to _______ in the big city.

I ________ work out the problem at first, but after my teacher showed me an example, I ________ get the answer easily.

 —What did you say to your sister? I saw her crying in the room.— It _________ my fault. I just said hello to her when I met her, nothing else.

I __________use a clock to wake me up because at six o'clock each morning the train comes by my house.