请问以下这句话中的about是否不是介词？
谢谢！
Between about 1910 and 1930, new artistic movements in european art were makin
g themselves felt in the United States.

http://www.ldoceonline.com/dictionary/about底下的定义二有你想要的答案这部分的确是adverb是说这个用法虽然很常见，但第一时间被问到词性时还是会在介系词和副词间犹豫一下因为about用在介系词的机会实在太多了

好的，谢谢sunny