Can you give _____some rice, please? [ ]
A. they
B. them
C. their
D. theirs
答案:B
氟乙酰胺中毒时的特效解毒剂是()
A.维生素K
B.二巯丙醇
C.纳洛酮
D.氟马西尼(安易醒)
E.乙酰胺(解氟灵)
已知A,B为3阶矩阵,且满足2A-1B=B-4E.其中E是3阶单位矩阵; (1)证明:矩阵A-2E可逆; (2)若B=[*],求矩阵A.