instruction:
This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
question:
In 121 BC, Han forces expelled the Xiongnu from a vast territory spanning the Hexi Corridor to Lop Nur. They repelled a joint Xiongnu-Qiang invasion of this northwestern territory in 111 BC. In that year, the Han court established four new frontier commanderies in this region: Jiuquan, Zhangyi, Dunhuang, and Wuwei. The majority of people on the frontier were soldiers. On occasion, the court forcibly moved peasant farmers to new frontier settlements, along with government-owned slaves and convicts who performed hard labor. The court also encouraged commoners, such as farmers, merchants, landowners, and hired laborers, to voluntarily migrate to the frontier.
answer:
Who made up a majority of the people on the frontier?


question:
Although several companies each produce over a billion individually packaged (known as discrete) transistors every year, the vast majority of transistors are now produced in integrated circuits (often shortened to IC, microchips or simply chips), along with diodes, resistors, capacitors and other electronic components, to produce complete electronic circuits. A logic gate consists of up to about twenty transistors whereas an advanced microprocessor, as of 2009, can use as many as 3 billion transistors (MOSFETs). "About 60 million transistors were built in 2002… for [each] man, woman, and child on Earth."
answer:
How many transistors make up a logic gate?


question:
Mexico City is served by Mexico City International Airport (IATA Airport Code: MEX). This airport is Latin America's second busiest and one of the largests in traffic, with daily flights to United States and Canada, mainland Mexico, Central America and the Caribbean, South America, Europe and Asia. Aeroméxico (Skyteam) is based at this airport, and provide codeshare agreements with non-Mexican airlines that span the entire globe. In 2014, the airport handled well over 34 million passengers, just over 2 million more than the year before. This traffic exceeds the current capacity of the airport, which has historically centralized the majority of air traffic in the country. An alternate option is Lic. Adolfo López Mateos International Airport (IATA Airport Code: TLC) in nearby Toluca, State of Mexico, although due to several airlines' decisions to terminate service to TLC, the airport has seen a passenger drop to just over 700,000 passengers in 2014 from over 2.1 million passengers just four years prior.
answer:

What is the name of the major airport in Mexico City?