题目内容：

    Have you ever seen a teenager or an adult riding a small bike? Perhaps it had posts sticking out from both sides of the wheels. 1.

BMX(自行车越野) bikes have a lightweight frame and smaller wheels than other bikes. 2. The sport of BMX began when kids wanted to copy off-speed motorcycle race that were very popular. Today it is a sport with multiple disciplines.

3. It is an exciting, fast-paced event with off-road tracks, jumps and bends. Up to eight riders race at a time. BMX street riding takes BMX off the competitive stage, and into the city for some fun. The goal is to do as many creative tricks as possible in the environment. BMX park riding originated when people started using skate parks, empty pools or parking lots, discovering new ways to ride. Later, the style was recognized as a sport and parks were created specially for riders to practise in. Lastly, BMX flatland riding differs from all the rest. Flatland uses nothing but a flat surface where the rider balances and does dance-like tricks on the bike. 4. The posts are called pegs and they enable the rider to do more tricks. They can stand on them in flatland BMX or use them to grind(摩擦)or stall in other styles of BMX.

5. But in reality, it is a sport over 65 years old. Contests such as the X Games and the Summer Olympics are putting BMX back in the spotlight.

A.where did the thrilling sport start?

B.BMX racing is the original form of BMX.

C.They are designed to be fast and user - friendly.

D.It is more than a sport with multiple disciplines.

E.Today BMX is known as a sport for the risk-takers.

F.What you saw was likely not a children's bike, but a BMX bike!

G.Riders of this style of BMX use posts sticking out of their bike wheels.