Add CoT format comment to the example snippet

README.md

@@ -109,6 +109,8 @@ messages = [
     # without CoT
     "Translate the following English sentence into Chinese:\nMay the force be with you <zh>",
     # with CoT
+    # The output of CoT prompt is `This is the translation text. \n\n[COT] This is the explanation.`
+    # Thus, you can use [COT] to extract the translation. If the model considers the input sentence to be relatively simple and does not require CoT, it will directly output the translated result without [COT].
     "Translate the following English sentence into Chinese and explain it in detail:\nMay the force be with you <zh>" 
 ]