W4 discussion 6000
Please write a primary reply (3 paragraphs with sources) to the topic, just like the examples. Write 2 secondary reply (1-2 paragraph each, with 1 source) to two of the examples.
Topic:
/Users/garyli/Desktop/WX20200311-175054@2x.png
Primary post example（short reply to 2 of them, 1-2 paragraph each）