The first survey was conducted in october 2004 . subsequent surveys will be conducted at six to twelve - month intervals 首次的行为风险因素调查已于二零零四年十月进行，期后的调查将每隔六至十二个月进行一次。
2.
The first survey was conducted in october 2004 . subsequent surveys will be conducted at six to twelve - month intervals 首次的行为风险因素调查已于二零零四年十月进行，期后的调查将每隔六至十二个月进行一次。
3.
" the surveillance system obtains information through telephone surveys that are conducted once to twice every year . the first survey was conducted in october 2004 . subsequent surveys will be carried out at six to twelve - month intervals 她说：监测系统是透过每年一至两次的电话调查取得资料，首次调查已于2004年10月进行，期后的调查将每隔6至12个月进行一次。
