Extend README slightly

README.md

@@ -44,7 +44,7 @@ configs:
 
 # MS MARCO Corpus
 
-This dataset allows for a convenient mapping from MS MARCO query/passage ID to the query/passage text. This corpus was downloaded from https://msmarco.z22.web.core.windows.net/msmarcoranking/collection.tar.gz.
+This dataset allows for a convenient mapping from MS MARCO query/passage ID to the query/passage text. This passage corpus was downloaded from https://msmarco.z22.web.core.windows.net/msmarcoranking/collection.tar.gz, and the queries from https://msmarco.blob.core.windows.net/msmarcoranking/queries.tar.gz (via Wayback Machine).
 
 ## Usage
 
@@ -52,7 +52,13 @@ This dataset was designed to allow you to perform the following:
 ```python
 from datasets import load_dataset
 
-dataset = load_dataset("sentence-transformers/msmarco-corpus", "query")
-id_to_text = dict(zip(dataset["qid"], dataset["text"]))
-print(id_to_text[571018])
+query_dataset = load_dataset("sentence-transformers/msmarco-corpus", "query", split="train")
+qid_to_query = dict(zip(query_dataset["qid"], query_dataset["text"]))
+print(qid_to_query[571018])
+# => "what are the liberal arts?"
+
+passage_dataset = load_dataset("sentence-transformers/msmarco-corpus", "passage", split="train")
+pid_to_passage = dict(zip(passage_dataset["pid"], passage_dataset["text"]))
+print(pid_to_passage[7349777])
+# => "liberal arts. 1. the academic course of instruction at a college intended to provide general knowledge and comprising the arts, humanities, natural sciences, and social sciences, as opposed to professional or technical subjects."
 ```