qǐng / jǐn / kuài / fù / xìn / gào / zhī / wǒ / shì / fǒu / cān / jiā / xià / zhōu / de / huì / yì / 。

请尽快复信告知我是否参加下周的会议。

Please reply as soon as possible to let me know if you will attend next week's meeting.