已知函数f(x)=(cos2xcosx+sin2xsinx)sinx,x∈R,则f(x)是( )
手握住瓶子,瓶子不掉下来,瓶受到的是( )
根的生长一方面靠____增加细胞的数量,一方面要靠____使细胞体积不断增大.
Peter ____(fly) his kite in the park last Saturday.