With no explanation, label text_A→text_B with either "strengthener" or "weakener".
text_A: A female speaker wearing a gray jacket, a dark scoop necked top with a dark knee length skirt is presenting to a group using a computer to present as well as a microphone at the podium. A college professor is giving a lesson in a big classroom.
text_B: Tired students yawn in their seats.
strengthener.