polish the texts

app.py

@@ -272,7 +272,7 @@ def start_or_resume(
             progress,
             "Please enter a non-empty identifier to begin.",
         )
-    if proficiency not in {"expert", "basic", "non-fluent"}:
+    if proficiency not in {"expert", "fluent", "basic"}:
         return (
             gr.update(value=user_id, visible=True),
             gr.update(visible=False),
@@ -481,7 +481,8 @@ Enter your identifier below to start or resume. Each sample is a pair of two sen
                 answer1_md = gr.Markdown(label="Sentence A", elem_classes=["answerbox"])
                 answer2_md = gr.Markdown(label="Sentence B", elem_classes=["answerbox"])
             choice_radio = gr.Radio(
-                ["Sentence 1", "Sentence 2"], label="Which sentence do you prefer?"
+                ["Sentence 1", "Sentence 2"],
+                label="Which sentence is more grammatically correct?",
             )
         submit_btn = gr.Button("Submit Preference", visible=False)