Updated Lessons 16, 17, 18

3 年之前 · 53c688ea3a
--- a/Lesson16/Lesson16.odp
+++ b/Lesson16/Lesson16.odp
--- a/Lesson16/Lesson16.pdf
+++ b/Lesson16/Lesson16.pdf
--- a/Lesson17/Lesson17.odp
+++ b/Lesson17/Lesson17.odp
--- a/Lesson17/Lesson17.pdf
+++ b/Lesson17/Lesson17.pdf
--- a/Lesson18/Lesson18.odp
+++ b/Lesson18/Lesson18.odp
--- a/Lesson18/Lesson18.pdf
+++ b/Lesson18/Lesson18.pdf