Input: Read this: An advantage of the universal motor is that AC supplies may be used on motors which have some characteristics more common in DC motors, specifically high starting torque and very compact design if high running speeds are used. The negative aspect is the maintenance and short life problems caused by the commutator. Such motors are used in devices such as food mixers and power tools which are used only intermittently, and often have high starting-torque demands. Multiple taps on the field coil provide (imprecise) stepped speed control. Household blenders that advertise many speeds frequently combine a field coil with several taps and a diode that can be inserted in series with the motor (causing the motor to run on half-wave rectified AC). Universal motors also lend themselves to electronic speed control and, as such, are an ideal choice for devices like domestic washing machines. The motor can be used to agitate the drum (both forwards and in reverse) by switching the field winding with respect to the armature.
Question: How is stepped speed control achieved?

Output: Multiple taps on the field coil provide

Input: Read this: Cities not served by road, sea, or river can be reached only by air, foot, dogsled, or snowmachine, accounting for Alaska's extremely well developed bush air servicesan Alaskan novelty. Anchorage and, to a lesser extent Fairbanks, is served by many major airlines. Because of limited highway access, air travel remains the most efficient form of transportation in and out of the state. Anchorage recently completed extensive remodeling and construction at Ted Stevens Anchorage International Airport to help accommodate the upsurge in tourism (in 2012-2013, Alaska received almost 2 million visitors).
Question: Which two cities are unserved by major airlines?

Output: unanswerable

Input: Read this: The Western family includes Parthian (Arsacid Pahlavi) and Middle Persian, while Bactrian, Sogdian, Khwarezmian, Saka, and Old Ossetic (Scytho-Sarmatian) fall under the Eastern category. The two languages of the Western group were linguistically very close to each other, but quite distinct from their eastern counterparts. On the other hand, the Eastern group was an areal entity whose languages retained some similarity to Avestan. They were inscribed in various Aramaic-derived alphabets which had ultimately evolved from the Achaemenid Imperial Aramaic script, though Bactrian was written using an adapted Greek script.
Question: Bactrian, Sogdian, and Saka are examples of what type of Iranian language?

Output: Eastern

Input: Read this: Zhejiang was the site of the Neolithic cultures of the Hemudu and Liangzhu. A 2007 analysis of the DNA recovered from human remains in the archeological sites of prehistoric peoples along the Yangtze River shows high frequencies of haplogroup O1 in the Liangzhu culture, linking them to Austronesian and Tai-Kadai peoples.
Question: What haplogroup did a DNA analysis of the Liangzhu culture not reveal?

Output:
unanswerable