diff --git a/pipelines.py b/pipelines.py
index 2c9c681..7701fd2 100644
--- a/pipelines.py
+++ b/pipelines.py
@@ -134,12 +134,14 @@ def _prepare_inputs_for_qg_from_answers_hl(self, sents, answers):
         for i, answer in enumerate(answers):
             if len(answer) == 0: continue
             for answer_text in answer:
-                sent = sents[i]
+                sent = sents[i].lower()
                 sents_copy = sents[:]
                 
-                answer_text = answer_text.strip()
-                
-                ans_start_idx = sent.index(answer_text)
+                answer_text = answer_text.strip().lower()
+                try:
+                    ans_start_idx = sent.index(answer_text)
+                except (ValueError,AssertionError):
+                    continue
                 
                 sent = f"{sent[:ans_start_idx]} <hl> {answer_text} <hl> {sent[ans_start_idx + len(answer_text): ]}"
                 sents_copy[i] = sent