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若$f\left(x\right)=2\cos \left(\omega x+\phi \right)+m$ 对任意实数$t$ 都有$f\left(t+\frac{\mathrm{\pi }}{4}\right)=f\left(-t\right)$ ，且$f\left(\frac{\mathrm{\pi }}{8}\right)=-1$，则实数$m$的值等于（   ）

    It is a rainy (阴雨的) day. A train stops at a small ____. A man is on the train and he feels hungry (饥饿的). He looks out of the window (窗) and sees a shop. A woman is ____ cakes in the shop and the cakes look ____. The man wants to ____ a cake, but the shop is a little (有点) ____ from the train. The man doesn't want to walk in the rain. Then he sees a boy. The boy is about five ____ old. He's playing near the window. "Come here, boy!" says the man, "Do you know how ____ the cake is?" "One dollar for one." says the boy. The man gives the boy two dollars and asks him to buy ____ cakes. "One is for you and the ____ is for me," he says to the boy.

    After some time, the boy comes back. He's eating a cake. He ____ the man one dollar. "Sorry, there is only one cake left (剩余). I eat the cake and here is one dollar back," says the boy.

下列二次根式中,最简二次根式是（  ）