表达式398: left bracket, left parenthesis, negative 1.5 , 3 , right parenthesis , left parenthesis, negative 1.5 , negative 2.5 , right parenthesis , left parenthesis, 8 , negative 2.5 , right parenthesis , left parenthesis, 8 , 3 , right parenthesis , left parenthesis, negative 1.5 , 3 , right parenthesis , right bracket−1.5,3,−1.5,−2.5,8,−2.5,8,3,−1.5,3