A:looked worrying;looked over
B:seemed like worried;looked after
C:looks worried;looked after
D:seemed worried;looked over
计算:
(1)(﹣13)﹣2+(136)0+(﹣5)3÷(﹣5)2;
(2)(2xy2)3﹣(5xy2)(﹣xy2)2.
甲数除以乙数(不为0)等于甲数乘乙数的倒数.
下列运算正确的是( )
下列有关物理量的估算,符合实际的是( )