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学生说明
After watching Introduction to Earthquakes (Frank Gregorio) https://www.youtube.com/watch?v=JrBaiPN6AW8, tap 
and use 
to share your thoughts on what an earthquake is and why they are so feared.
to add to your journal.
教师备注（学生不可见）
Image retrieved from https://metro.co.uk/2018/05/15/new-zealand-hit-by-fifteen-earthquakes-in-quick-succession-sparking-fears-of-big-one-7546961/
