Update README.md

README.md

@@ -26,9 +26,8 @@ pretty_name: TweetNER7
 
 
 ### Dataset Summary
-This is an official of TweetNER7 ("Named Entity Recognition in Twitter:
-A Dataset and Analysis on Short-Term Temporal Shifts, AACL main conference 2022"), an NER dataset on Twitter with 7 entity labels. Each instance of TweetNER7 comes with
-a timestamp which distributes from September 2019 to August 2021.
+This is the official repository of TweetNER7 ("Named Entity Recognition in Twitter:
+A Dataset and Analysis on Short-Term Temporal Shifts, AACL main conference 2022"), an NER dataset on Twitter with 7 entity labels. Each instance of TweetNER7 comes with a timestamp which distributes from September 2019 to August 2021.
 - Entity Types: `corperation`, `creative_work`, `event`, `group`, `location`, `product`, `person` 
 
 ### Preprocessing
@@ -92,6 +91,9 @@ We ask annotators to ignore those special tokens but label the verified users' m
 | extra_2020        | 87880 | extra tweet without annotations from September 2019 to August 2020 |
 | extra_2021        | 93594 | extra tweet without annotations from September 2020 to August 2021 |
 
+For the temporal-shift setting, model should be trained on `train_2020` with `validation_2020` and evaluate on `test_2021`.
+In general, model would be trained on `train_all`, the most representative training set with `validation_2021` and evaluate on `test_2021`.
+
 
 ### Models