diff --git a/Controllers/SubmissionController.cs b/Controllers/SubmissionController.cs
index 677045f..da9e610 100644
--- a/Controllers/SubmissionController.cs
+++ b/Controllers/SubmissionController.cs
@@ -44,7 +44,7 @@ namespace _2021_backend.Controllers
 
             var stu = context.Students.FirstOrDefault(e => e.Stuid == stuid);
             if (stu == null) return Ok(ApiResponse.Error("INVALID_STUID"));
-            else if (DateTime.Now - stu.LastCaptchaTime < TimeSpan.FromMinutes(1)) return Ok(ApiResponse.Error("ALREADY_SENT"));
+            else if (DateTime.Now - stu.LastCaptchaTime < TimeSpan.FromMinutes(1)) return Ok(ApiResponse.Error($"ALREADY_SENT,{DateTime.Now.ToString("f")},{stu.LastCaptchaTime.ToString("f")}"));
             var result = await TencentSMS.Send(context, SMSType.Captcha, stu, "smsbot");
             if (!result) return Ok(ApiResponse.Error("SEND_ERROR"));
             return Ok(ApiResponse.Success("success"));