知识点梳理

 

/uploads/allimg/181210/143T445O-0.jpg
/uploads/allimg/181210/143T46305-1.jpg
/uploads/allimg/181210/143T432R-2.jpg

 

 

 

 

视频讲解



 

 

 

 

 

 

练习

/uploads/allimg/181210/143T4J92-3.jpg

/uploads/allimg/181210/143T41633-4.jpg
/uploads/allimg/181210/143T44362-5.jpg/uploads/allimg/181210/143T4D06-6.jpg