A COOK admitted aiding and abetting three mainlanders to use forged travel documents to fly from Hong Kong to the United States, the District Court heard. Yeung Kei-kong, 38, yesterday pleaded guilty to three charges of aiding, abetting, counselling or procuring the use of a forged permit to re-enter the US and another three of aiding, abetting, counselling or procuring the making of a false representationto an immigration official. Prosecutor Christopher Grounds said Jiang Lingfeng, Huang Xiuzhen and Chen Shubin travelled from Fuzhou to Singapore to meet Yeung last January. Two months later, he and the three flew from Singapore to Hong Kong. Yeung gave each of them a false US document and an arrival card, but they failed to get past the immigration counter at Kai Tak airport. Yeung was found 11 days later, when he tried to go to Macau. Judge Hawkes remanded him in custody until sentencing on January 10.