In Britain there is a National Health Service (NHS) which is paid for by taxes （税收）and National Insurance（保险）,and in general people do not have to pay for medical treatment.Every person is registered with a doctor in his or her localarea,known as a general practitioner(全科医生) or GP.This means that their names are on the GP’s list,and they may make an appointment（约见）to see the doctor or may call the doctor out to visit them if they are ill.People sometimes do have to pay part of the cost of drugs that the doctor prescribes.GPs are trained in general medicine but are not specialists in any particular subject.If a patient needs to see a specialist doctor,they must first go to their GP and then the GP will make an appointment for the patient to see a specialist at a hospital or clinic.Although everyone in Britain can have free treatment under the NHS,it is also possible for him to have treatment done privately,for which he has to pay.Some people have private health insurance to help them pay for private treatment.Under the NHS,people who need to go to hospital may have to wait for a long time on a waiting list for their treatment.Anyone who is very ill can call an ambulance(救护车)and get taken to hospital for free urgent medical treatment.Ambulances are a free service in Britain.21.In Britain,the National Health Service refers to（）.A.a local hospitalB.a medicine supplier C.a medical care systemD.an insurance company 22.Under the National Health Service,British citizens（）.A.are all registered with a general practitioner B.do not need to buy private health insurance C.can only go to see a general practitioner D.can not call in a general practitioner 23.People buy private health insurance in order to（）.A.pay for the ambulance service B.receive free urgent treatment C.see a general practitioner D.have private treatment 24.Which of the following is TURE according to the passage? （）A.People in Britain do not have to pay for any kind of medical care.B.People in Britain may wait long for their free medical treatment.C.In Britain you have to pay for ambulance service.D.Britain private medical insurance is free.25.What is this passage mainly about? （）A.Private medical care in Britain.B.Roles of general practitioners.C.Taxes and free medical care.D.Health services in Britain.