The English modal verbs are a subset of the English auxiliary verbs used mostly to express modality (properties such as possibility, obligation, etc.). They can be distinguished from other verbs by their defectiveness (they do not have participle or infinitive forms) and by their neutralization (that they do not take the ending -(e)s in the third-person singular).
The principal English modal verbs are can, could, may, might, shall, should, will, would, and must. Certain other verbs are sometimes, but not always, classed as modals; these include ought, had better, and (in certain uses) dare and need. Verbs which share only some of the characteristics of the principal modals are sometimes called "quasi-modals", "semi-modals", or "pseudo-modals".A train is a form of rail transport consisting of a series of connected vehicles that generally run along a railroad (or railway) track to transport passengers or cargo (also known as "freight" or "goods"). The word train comes from the Old French trahiner, derived from the Latin trahere meaning 'to pull, to draw'.Motive power for a train is provided by a separate locomotive or individual motors in a self-propelled multiple unit. The term "engine" is often used as an alternative to locomotive. Although historically steam propulsion dominated, the most common types of locomotive are diesel and electric, the latter supplied by overhead wires or additional rails. Trains can also be hauled by horses, pulled by engine or water-driven cable or wire winch, run downhill using gravity, or powered by pneumatics, gas turbines or electric batteries.
The track usually consists of two running rails with a fixed spacing, which may be supplemented by additional rails such as electric conducting rails ("third rail") and rack rails. Monorails and maglev guideways are also occasionally used.Passenger trains include passenger-carrying vehicles and can often be very long and fast. High-speed rail systems began expanding rapidly in the late 20th century, and this remains a major subject of further development. The term "light rail" is sometimes used to refer to a modern tram system, but it may also mean an intermediate form between a tram and a train, similar to a heavy rail rapid transit system.
Freight (goods) trains use freight cars (or wagons/trucks) to transport goods or materials (cargo). It is possible to carry passengers and freight in the same train using a mixed consist.
Rail cars and machinery that are used for the maintenance and repair of tracks, are termed "maintenance of way" equipment; these may be assembled into maintenance of way trains. Similarly, dedicated trains may be used to provide support services to stations along a train line, such as garbage or revenue collection.An invasion is a military offensive in which large numbers of combatants of one geopolitical entity aggressively enter territory owned by another such entity, generally with the objective of either conquering; liberating or re-establishing control or authority over a territory; forcing the partition of a country; altering the established government or gaining concessions from said government; or a combination thereof. An invasion can be the cause of a war, be a part of a larger strategy to end a war, or it can constitute an entire war in itself. Due to the large scale of the operations associated with invasions, they are usually strategic in planning and execution.Privacy (UK: , US: ) is the ability of an individual or group to seclude themselves or information about themselves, and thereby express themselves selectively.
When something is private to a person, it usually means that something is inherently special or sensitive to them. The domain of privacy partially overlaps with security, which can include the concepts of appropriate use and protection of information. Privacy may also take the form of bodily integrity. The right not to be subjected to unsanctioned invasions of privacy by the government, corporations, or individuals is part of many countries' privacy laws, and in some cases, constitutions.
In the field of business, a person may volunteer personal details, including for advertising, in order to receive some kinds of benefit. Public figures may be subject to rules on the public interest. Personal information which is voluntarily shared but subsequently stolen or misused can lead to identity theft.
The concept of universal individual privacy is a modern concept primarily associated with Western culture, particularly British and North American, and remained virtually unknown in some cultures until recent times. Most cultures, however, recognize the ability of individuals to withhold certain parts of their personal information from wider society, such as closing the door to one's home.