胶质瘤术后放疗后复发与放射性坏死的鉴别技术是（）
A.MRS
B.PWI
C.DWI
D.Gd-MRI
E.FLAIR
参考答案：A, B
I saw some workers ____ the square when I went home.[ ]
A. cleaning
B. cleaned
C. to clean
D. clean
高尔基的代表作有《海燕》、《童年》等。( )
