diff --git a/src/args.rs b/src/args.rs
index 5de5cf5..da0aa2c 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -394,6 +394,10 @@ pub struct Arg {
     #[arg(short = 'L', long, global = true, default_value_t = 5, value_parser = parse_flac_compression_level)]
     /// FLAC compression level for output FLAC audio files. 0 means fastest compression, 8 means best compression.
     pub flac_compression_level: u32,
+    #[arg(long, global = true)]
+    /// Add a mark to the end of each message for LLM translation.
+    /// Only works on m3t format.
+    pub llm_trans_mark: Option<String>,
     #[command(subcommand)]
     /// Command
     pub command: Command,
diff --git a/src/main.rs b/src/main.rs
index 030f2ff..71f6055 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1101,7 +1101,10 @@ pub fn import_script(
                                 continue;
                             }
                         };
-                        let mut parser = output_scripts::m3t::M3tParser::new(&s);
+                        let mut parser = output_scripts::m3t::M3tParser::new(
+                            &s,
+                            arg.llm_trans_mark.as_ref().map(|s| s.as_str()),
+                        );
                         match parser.parse() {
                             Ok(mes) => mes,
                             Err(e) => {
@@ -1320,7 +1323,10 @@ pub fn import_script(
             let enc = get_output_encoding(arg);
             let b = utils::files::read_file(&out_f)?;
             let s = utils::encoding::decode_to_string(enc, &b, true)?;
-            let mut parser = output_scripts::m3t::M3tParser::new(&s);
+            let mut parser = output_scripts::m3t::M3tParser::new(
+                &s,
+                arg.llm_trans_mark.as_ref().map(|s| s.as_str()),
+            );
             parser.parse()?
         }
         types::OutputScriptType::Yaml => {
diff --git a/src/output_scripts/m3t.rs b/src/output_scripts/m3t.rs
index abadca4..a3f0016 100644
--- a/src/output_scripts/m3t.rs
+++ b/src/output_scripts/m3t.rs
@@ -15,12 +15,17 @@ use anyhow::Result;
 pub struct M3tParser<'a> {
     str: &'a str,
     line: usize,
+    llm_mark: Option<&'a str>,
 }
 
 impl<'a> M3tParser<'a> {
     /// Creates a new M3tParser with the given string.
-    pub fn new(str: &'a str) -> Self {
-        M3tParser { str, line: 1 }
+    pub fn new(str: &'a str, llm_mark: Option<&'a str>) -> Self {
+        M3tParser {
+            str,
+            line: 1,
+            llm_mark,
+        }
     }
 
     fn next_line(&mut self) -> Option<&'a str> {
@@ -68,16 +73,31 @@ impl<'a> M3tParser<'a> {
                     .is_empty()
                 {
                     llm.take()
+                        .map(|s| {
+                            let mut s = s.to_string();
+                            if let Some(mark) = self.llm_mark {
+                                s.push_str(mark);
+                            }
+                            s
+                        })
                         .unwrap_or_else(|| {
-                            if message.starts_with("「") {
+                            String::from(if message.starts_with("「") {
                                 "「」"
                             } else {
                                 ""
-                            }
+                            })
                         })
                         .replace("\\n", "\n")
                 } else {
-                    message.replace("\\n", "\n")
+                    let mut tmp = message.replace("\\n", "\n");
+                    if let Some(llm) = llm.take() {
+                        if tmp == llm {
+                            if let Some(mark) = self.llm_mark {
+                                tmp.push_str(mark);
+                            }
+                        }
+                    }
+                    tmp
                 };
                 messages.push(Message::new(message, name.take()));
             } else {