----- Nội dung dịch tự động từ ảnh ----- Mully up the 1970skeboarding soddenly became very popular. At f s moved slowly on flat, smooth areas. Then they began to dfestyle' skateboarding, Soon they were skateboardi dong tricks in the air. This is called ramp skateboarding. Then they hoarding and doing tricks on the street. This was barding combination of freestyle and ramp. For this, the skateboarders protective clothing such as knee and elbow pads and helmers. This allowed them to skateboard safely. Today skateboarding is still a very popular sport, and there are lots of When did skateboarding become very popolar What are the tree styles of skateboarding? What was 'street-style' skateboarding? Why do "street-style skateboarders need protective clothing? De Shunk skateboarding is a very popular sport now? Why or why not?