前兆
Forewarn \Fore*warn"\, v. t. [imp. & p. p. {Forewarned}; p. pr. & vb. n. {Forewarning}.] To warn beforehand; to give previous warning, admonition, information, or notice to; to caution in advance. We were forewarned of your coming. --Shak.
forewarning n : an early warning about a future event [syn: {premonition}]