The students can't ______ TV. [ ]
A. watch always
B. always watches
C. always watch
答案:C
下面哪一项乳腺病变或结构不伴有后方回声增强()。
A.囊肿
B.脂肪小叶
C.扩张的导管
D.纤维腺瘤
E.脓肿
土坝护面的横向坡度宜采用( )。
A.10%
B.2%~3%
C.50%
D.100%