20.There used__________a post office at the corner of the street.
As there was just one vacant position, all the candidates tried their best to leave a favorable ______ on the interviewer to make themselves stand out.
Tomorrow being the last day, you should hand in your composition by emails to meet the ______.
My father bought me several books, but _____ was interesting.
He failed in the exam, ______ proves that he wasn’t working hard enough.
The girl got herself into a serious situation ______ she was likely to lose control over the bike.