This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
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Question: Passage: Modern electrification systems take AC energy from a power grid which is delivered to a locomotive and converted to a DC voltage to be used by traction motors. These motors may either be DC motors which directly use the DC or they may be 3-phase AC motors which require further conversion of the DC to 3-phase AC (using power electronics). Thus both systems are faced with the same task: converting and transporting high-voltage AC from the power grid to low-voltage DC in the locomotive. Where should this conversion take place and at what voltage and current (AC or DC) should the power flow to the locomotive? And how does all this relate to energy-efficiency? Both the transmission and conversion of electric energy involve losses: ohmic losses in wires and power electronics, magnetic field losses in transformers and smoothing reactors (inductors). Power conversion for a DC system takes place mainly in a railway substation where large, heavy, and more efficient hardware can be used as compared to an AC system where conversion takes place aboard the locomotive where space is limited and losses are significantly higher. Also, the energy used to blow air to cool transformers, power electronics (including rectifiers), and other conversion hardware must be accounted for. Question: What nowdays electrification systems can use?

Answer: DC motors which directly use the DC or they may be 3-phase AC motors


Question: Passage: Despite the lack of a coastline, Punjab is the most industrialised province of Pakistan; its manufacturing industries produce textiles, sports goods, heavy machinery, electrical appliances, surgical instruments, vehicles, auto parts, metals, sugar mill plants, aircraft, cement, agricultural machinery, bicycles and rickshaws, floor coverings, and processed foods. In 2003, the province manufactured 90% of the paper and paper boards, 71% of the fertilizers, 69% of the sugar and 40% of the cement of Pakistan. Question: How much of Pakistan's paper products does Punjab manufacture?

Answer: 90%


Question: Passage: In 1348 and 1349 Portugal, like the rest of Europe, was devastated by the Black Death. In 1373, Portugal made an alliance with England, which is the longest-standing alliance in the world. This alliance served both nations' interests throughout history and is regarded by many as the predecessor to NATO. Over time this went way beyond geo-political and military cooperation (protecting both nations' interests in Africa, the Americas and Asia against French, Spanish and Dutch rivals) and maintained strong trade and cultural ties between the two old European allies. Particularly in the Oporto region, there is visible English influence to this day. Question: In 1373, Portugal made an alliance with which country?

Answer:
England