Update README.md

README.md

@@ -52,9 +52,9 @@ The file contains the answer corresponds to the question [id].
 #### 3. trace/[id].json
 The file conatins the human trajectory of the question [id], with the following keys:
 
-- search: the queries issued by the annotator
-- result: the search result of each query
-- click: the click behavior made by the annotator
+- search (list): the queries issued by the annotator
+- result (dict): the search result of each query
+- click (list): the click behaviors made by the annotator
 
 ## Loading Method