Q: This task involves creating questions from a given passage that involve some kind of complex reasoning (including numerical reasoning).
The generated questions must require looking at more than one part of the passage to answer. Try to use a variety of reasoning types in your questions (some of the sample reasoning types are illustrated in the 'positive examples' field) and also have a variety of answer types (spans, numbers, dates). A span is a continuous phrase taken directly from the passage or question. In such questions, the answer spans are recommended to be five words. Questions with answer type "number", are expected to start with "How many". For instance, "How long did an event last?" can be phrased as "How many years did an event last?". To increase diversity, try to create more questions for which the answer will be multiple spans. Please create questions that require AT LEAST 2 arithmetic operations as illustrated in the 'positive examples' field. You are encouraged to try DIFFERENT COMBINATIONS of operations and not just limit to the combinations shown in those examples. The more challenging questions you create, the better it is.
Passage: The Lines of Communication were English Civil War fortifications commissioned by Parliament and built around London between 1642 and 1643 to protect the capital from attack by the Royalist armies of Charles I. In 1642 some basic fortifications were built, in the form of street barricades and small earthworks. In 1643 a major construction effort was made, to provide a comprehensive ring of fortifications around the city. Much of the work was done by volunteer labour, organized by the trained bands and the livery companies. Up to 20,000 people are thought to be involved, and the works were completed in under two months. The fortifications failed their only test when the New Model Army entered London in 1647, and they were levelled by Parliament the same year.
A:
How many months did it take them to build The Lines of Communication?