An ant was drinking by a small river when it fell in.It made ______ efforts to reach the side,but made no progress at all.
A:negative
B:total
C:desperate
D:careful
(Ⅰ)求实数a的值;
(Ⅱ)试判断函数f(x)在(﹣∞,+∞)上的单调性,并证明你的结论;
(Ⅲ)若对任意的t∈R,不等式f(t2﹣(m﹣2)t)+f(t2﹣m﹣1)<0恒成立,求实数m的取值范围.
关于T细胞的叙述,错误的是( )
如图关于电饭锅的说法错误的是( )
17-9=( )