The flowers _______ sweet in the botanic garden attract the visitors to the beauty of nature.?

A. to smell　B. smelling?

C. smelt D. to be smelt?

Mrs. Brown was much disappointed to see the washing machine she had had____ went wrong again.?　

A. it    B. it repaired    C. repaired    D. to be repaired?

While he was investigating ways to improve the telescope, Newton made ______ discovery which completely changed ______ man’s understanding of colour.

A. a; 不填 B. a; the　　C. 不填; the D. the; a

The collapse of the World Trade Centre  has put US economy in a difficult  ___________.

A. occasion                  B. case        C. situation　       D. background

This bird is really lovely， and I’ve never seen ______ one.

　　A. a finer     B. a finest    C. the finer D. the finest