—May I go out tonight?—Of course you can, _____ you promise to be back before 10 o’clock.
- Do you go there ____ bus? - No, we go there ____ a train.
Many people are still ____ the habit of writing silly things ____ public places.
In Hangzhou Mr Green was so struck ____ the beauty of nature that he stayed ____ another night.
He is running ____ the wind towards the east of the station ____ Tom is running ____ the right.
I don't think you can work out the maths problem ____ the teacher's help.