Miss White see some school things ____the teacher's desk. They are a pencil box, a red pencil, two black ____(pen), a blue watch and an ____ notebook. Whose are they?

    Miss White asks Tina, “Tina, is this ____pencil box?”Tina says, “Yes, it is. Thank you.” “Are____(this) your pens?” asks Miss White. “No, they ____.They're____(Lucy).” says Tina.

Miss White goes to Lucy and says, “ Are they your pens, Lucy?” Lucy says, “Yes, they are. Thank you.” “What____ the red pencil? Is it ____(you), too?” Miss White asks. “ No, it isn't.” says Lucy. “And the watch and the aren't mine, either(也).” “Oh, I can put them____the lost and found box.” says Miss White.

马克思强调，任何真正的哲学都是自己时代的精神上的精华。因为真正的哲学（   ）。

①正确地总结了时代的实践经验②牢牢地把握住了时代的脉搏③正确地反映了时代的任务和要求④正确地概括了时代的认识成果

已知$f_1\left(x\right)=\cos x,f_2\left(x\right)=f_1^{\text{'}}\left(x\right),f_3\left(x\right)=f_2^{\text{'}}\left(x\right),f_4\left(x\right)=f_3^{\text{'}}\left(x\right),...f_n\left(x\right)=f_{n-1}^{\text{'}}\left(x\right)$则$f_{2013}\left(x\right)=$ （ ）