Warning: Undefined array key 1 in D:\INETPUB\VHOSTS\luhui.net\httpdocs\de\index.php on line 138 In order to derive the answer we needed to solve the mathematical equation. - 鲁虺德汉词典 Warning: Undefined array key 1 in D:\INETPUB\VHOSTS\luhui.net\httpdocs\de\index.php on line 220