这位美国研究专家正在撰写一本关于20世纪美国文学的著作。

The ___Americanist is writing a book on 20th-century American literature.

这位教授是一位坚定的美国主义者，经常在讲座中宣扬美国的民主理念。

The professor is a devoted ___Americanist who often promotes democratic values in his lectures.