Problem: Additionally, there are issues of connections between different electrical services, particularly connecting intercity lines with sections electrified for commuter traffic, but also between commuter lines built to different standards. This can cause electrification of certain connections to be very expensive simply because of the implications on the sections it is connecting. Many lines have come to be overlaid with multiple electrification standards for different trains to avoid having to replace the existing rolling stock on those lines. Obviously, this requires that the economics of a particular connection must be more compelling and this has prevented complete electrification of many lines. In a few cases, there are diesel trains running along completely electrified routes and this can be due to incompatibility of electrification standards along the route.
Why are disel trains  still used on electrified routes?
The answer is the following: due to incompatibility of electrification standards

Problem: Beyoncé has received numerous awards. As a solo artist she has sold over 15 million albums in the US, and over 118 million records worldwide (a further 60 million additionally with Destiny's Child), making her one of the best-selling music artists of all time. The Recording Industry Association of America (RIAA) listed Beyoncé as the top certified artist of the 2000s, with a total of 64 certifications. Her songs "Crazy in Love", "Single Ladies (Put a Ring on It)", "Halo", and "Irreplaceable" are some of the best-selling singles of all time worldwide. In 2009, The Observer named her the Artist of the Decade and Billboard named her the Top Female Artist and Top Radio Songs Artist of the Decade. In 2010, Billboard named her in their "Top 50 R&B/Hip-Hop Artists of the Past 25 Years" list at number 15. In 2012 VH1 ranked her third on their list of the "100 Greatest Women in Music". Beyoncé was the first female artist to be honored with the International Artist Award at the American Music Awards. She has also received the Legend Award at the 2008 World Music Awards and the Billboard Millennium Award at the 2011 Billboard Music Awards.
How many copies of her albums as Beyonce sold in the US?
The answer is the following: 15 million

Problem: Boston is sometimes called a "city of neighborhoods" because of the profusion of diverse subsections; the city government's Office of Neighborhood Services has officially designated 23 neighborhoods.
How many neighborhoods are in Boston?
The answer is the following: 23 neighborhoods

Problem: Uranium is more plentiful than antimony, tin, cadmium, mercury, or silver, and it is about as abundant as arsenic or molybdenum. Uranium is found in hundreds of minerals, including uraninite (the most common uranium ore), carnotite, autunite, uranophane, torbernite, and coffinite. Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores (it is recovered commercially from sources with as little as 0.1% uranium).
What is the most prevalent uranium ore?
The answer is the following:
uraninite