单词	级函数
释义	级函数step function
随便看	believed believe in believe in one's star believe in (或trust to) one's star believe it or not believe me believe of believe on believe one's ears believe one's eyes believe one's (own) eyes believe one's own eyes believer believers believes believe someone on his bare word believe someone's bare word believe someone's (或 someone on his) bare word believe someone to believe that the moon is made of green cheese believe that water can flow uphill believe (that) water can (或 will) flow uphill believe that water will flow uphill believe the negative rule believe the positive rule