34One of the most important reasons for a pre-listening activity in elementary schools is to______________ .
(A) activate existing prior knowledge and introduce missing prior knowledge
(B) emphasize the overall grammatical structure of the lesson
(C) check and discuss students’ responses to the while-listening task
(D) let students make their own contributions to their own studying

Three teaching stages

Pre-listening: help students prepare to listen

While-listening: guide and help students to comprehend the text

Post-listening: help them to integrate what they learned from the text into existing knowledge

Pre-listening

Pre-listening activities are things learners do before a listening activity in order to prepare for listening. These activities have various purposes, including pre-teaching or activating vocabulary, predicting content, generating interest and checking understanding of task.

Example 
The learners are going to listen to a radio programme about sharks. First, they work in groups to pool their knowledge of sharks and then tell the rest of the class.

In the classroom 
Pre-listening tasks include discussion questions, true or false statements, vocabulary work, prediction tasks and brainstorming the topic.

資料來源 https://www.teachingenglish.org.uk/article/pre-listening