Simplify the following text for a Grade 10 native English-speaking person.
Original: When Strasberg felt Monroe was ready to give a performance in front of her peers , Monroe and Maureen Stapleton chose the opening scene from Eugene O'Neill 's Anna Christie , and although she had faltered during each rehearsal , she was able to complete the performance without forgetting her lines .
Simplified: When Strasberg felt Monroe was ready to give a performance in front of her peers , Monroe and Maureen Stapleton chose the opening scene from Eugene O'Neill 's Anna Christie . Monroe had performed poorly during each rehearsal , she was able to complete the performance without forgetting her lines .