Warning: file_put_contents(/www/wwwroot/zidian/biehu.cn/cache/66e3cf6030132afde808c51fe0ef2cea.txt): failed to open stream: No space left on device in /www/wwwroot/zidian/biehu.cn/index.php on line 58 backward difference approximation是什么意思，backward difference approximation的翻译，backward difference approximation音标、读音、用法和例句_甲百汇小鸡词典