Problem: Given the question: Extract the answer to the question from the following context. Question: When was London made the capital of England? Context: Within London, both the City of London and the City of Westminster have city status and both the City of London and the remainder of Greater London are counties for the purposes of lieutenancies. The area of Greater London has incorporated areas that were once part of the historic counties of Middlesex, Kent, Surrey, Essex and Hertfordshire. London's status as the capital of England, and later the United Kingdom, has never been granted or confirmed officiallyby statute or in written form.[note 6]
++++++++++++++++++++++++++++++++
The answer is:
never

Problem: Given the question: Extract the answer to the question from the following context. Question: What is isoniazid used for? Context: Treatment of TB uses antibiotics to kill the bacteria. Effective TB treatment is difficult, due to the unusual structure and chemical composition of the mycobacterial cell wall, which hinders the entry of drugs and makes many antibiotics ineffective. The two antibiotics most commonly used are isoniazid and rifampicin, and treatments can be prolonged, taking several months. Latent TB treatment usually employs a single antibiotic, while active TB disease is best treated with combinations of several antibiotics to reduce the risk of the bacteria developing antibiotic resistance. People with latent infections are also treated to prevent them from progressing to active TB disease later in life. Directly observed therapy, i.e., having a health care provider watch the person take their medications, is recommended by the WHO in an effort to reduce the number of people not appropriately taking antibiotics. The evidence to support this practice over people simply taking their medications independently is poor. Methods to remind people of the importance of treatment do, however, appear effective.
++++++++++++++++++++++++++++++++
The answer is:
TB treatment

Problem: Given the question: Extract the answer to the question from the following context. Question: Which one contains imurity, copper or bronze? Context: The major applications of copper are in electrical wires (60%), roofing and plumbing (20%) and industrial machinery (15%). Copper is mostly used as a pure metal, but when a higher hardness is required it is combined with other elements to make an alloy (5% of total use) such as brass and bronze. A small part of copper supply is used in production of compounds for nutritional supplements and fungicides in agriculture. Machining of copper is possible, although it is usually necessary to use an alloy for intricate parts to get good machinability characteristics.
++++++++++++++++++++++++++++++++
The answer is:
bronze