The medical term for a broken bone is a fracture．But there are different kinds of fractures．A single fracture is when a bone is broken in just one place．You may have heard the term hairline fracture．This is a single fracture that is very small，like the width of a hair．A complete fracture is when the bone comes apart．When a bone is broken in more than two places or gets crushed，the name for it is a comminuted fracture．Still another condition is called a bowing fracture．This happens with a bone that bends but does not break．It happens mostly in children．Ever heard of a greenstick fracture? This is when a bone is．bent and breaks along only one side，like a young stick of wood．Another kind of break is an open or compound fracture．This is when the bone breaks the skin．This is very serious．Along with the bone damage there is a risk of infection in the open wound．
A lot of things happen as the body reacts to an injury like a broken bone．You might suddenly feel lightheaded．You might also feel sick to your stomach．People who are seriously injured can go into shock．They might feel cold，dizzy and unable to think clearly．Shock requires immediate medical attention．But while broken bones can be painful，they are generally not rife-threatening．Still，broken bones should be treated quickly because they can restrict blood flow or cause nerve damage．Also，the break will start to repair itself，so you want to make sure the bone is lined up correctly．
X-rays are taken to see the break．Treatment depends on the kind of fracture that is identified．A doctor sets a broken bone to make sure it is in the correct position．Severe breaks may require an operation to hold the bone together with metal plates and screws．Then，a hard cast may be put around the area of the break to hold the bone in place while it heals．Casts are usually worn for one to two months．In some cases，instead of a cast，a splint made of plastic or metal will be secured over the area to restrict movement．
1．How many kinds of fractures are mentioned in this passage?
A．Four． B．Five． C．Six． D．Seven．
2．If a bone is bent but does not break，it belongs to _________．
A．a hairline fracture B．a bowing fracture
C．a greenstick fracture D．an open fracture
3．What's the main idea of the second paragraph?
A．Reactions of the body to a broken bone．
B．Various results from broken bones．
C．People's worries about broken bones．
D．People's performance after a broken bone．
4．What's the main idea of the last paragraph?
A．How to identify a broken bone．
B．How to treat a broken bone．
C．What is needed in treating a broken bone．
D．Why are X-rays needed for a broken bone．
5．What's the meaning of “cast” in the last paragraph?
A．A sprint made of plastic or metal．
B．A thin pointed piece of metal used to fasten something．
C．A hard protective case used to support a broken bone．
D．A shaped container to make an object into a particular shape．