你务必于下午两点半来参加会议的英文

be sure to attend the meeting at half past two in the afternoon

• 你:    you
• 务必:    must; be sure to
• 下午:    afternoon; post me ...
• 两:    two
• 点:    drop
• 半:    half
• 来:    come; arrive
• 参加会议:    attend a meeting