gradually       
adverb uk/ˈɡrædʒ.u.ə.li/ us/ˈɡrædʒ.u.ə.li/
B2 逐步地,逐渐地;平缓地
slowly over a period of time or a distance
  Gradually, she realized that he wasn't telling her the truth. 她渐渐地意识到他不跟她说实话。 
 The bank slopes gradually down to the river. 河岸平缓地向下一直延伸到水边。 
 - More examples
 - The sound of his footsteps gradually died away.
 - The bank slopes gradually down to the river.
 - The painful memories gradually receded in her mind.
 - As the plot unfolds, you gradually realize that all your initial assumptions were wrong.
 - Those who disagreed with the director's viewpoint were gradually edged out of the company.