71.English has become a communication _______ for people from different countries.
72.During the eight years war, many people _______ their blood for their country.
73.You have greatly _______us. What you have done is not what you told us about several weeks ago.
74.Before you begin writing your paper, please write ------__________ first. Then we can have a better idea about what you are going to talk about.
75.If you ask why I plan to study in the United States, the only answer is that it is a _______ for me .