1. What Are Modal Verbs?

Speakers and Sound Card - Computers need both a sound card and speakers to hear audio, such as music, speech and sound effects. Most motherboards provide an on-board sound card. This built-in-sound card is fine for the most purposes. The basic functions of a sound card are that it converts digital sound signals to analog for speakers making it louder or softer.


3.Electronic email
Electronic mail (email or e-mail) is a method of transmitting and receiving messages using electronic devices. It was conceived in the late–20th century as the digital version of, or counterpart to, mail(hence e- + mail). Email is a ubiquitous and very widely used communication medium; in current use, an email address is often treated as a basic and necessary part of many processes in business, commerce, government, education, entertainment, and other spheres of daily life in most countries.

This screenshot shows the "Inbox" page of an email client; users can see new emails and take actions, such as reading, deleting, saving, or responding to these messages.

When a "robot" on Wikipediamakes changes to image files, the uploader receives an email about the changes made.
Email operates across computer networks, primarily the Internet, and also local area networks. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simultaneously; they need to connect, typically to a mail server or a webmailinterface to send or receive messages or download it.
Originally an ASCII text-only communications medium, Internet email was extended by Multipurpose Internet Mail Extensions (MIME) to carry text in other character sets and multimedia content attachments. International email, with internationalized email addresses using UTF-8, is standardized but not widely adopted.
Computer-based messaging between users of the same system became possible after the advent of time-sharing in the early 1960s, with a notable implementation by MIT's CTSS project in 1965.[23] Most developers of early mainframes and minicomputers developed similar, but generally incompatible, mail applications. In 1971 the first ARPANETnetwork mail was sent, introducing the now-familiar address syntax with the '@' symbol designating the user's system address Over a series of RFCs, conventions were refined for sending mail messages over the File Transfer Protocol. 
Proprietary electronic mail systems soon began to emerge. IBM, CompuServe and Xerox used in-house mail systems in the 1970s; CompuServe sold a commercial intraoffice mail product from 1978 and IBM and Xerox from 1981. DEC's ALL-IN-1 and Hewlett-Packard's HPMAIL (later HP DeskManager) were released in 1982; development work on the former began in the late 1970s and the latter became the world’s largest selling email system.
The Simple Mail Transfer Protocol (SMTP) protocol was implemented on the ARPANET in 1983. LAN email systems emerged in the mid 1980s. For a time in the late 1980s and early 1990s, it seemed likely that either a proprietary commercial system or the X.400 email system, part of the Government Open Systems Interconnection Profile (GOSIP), would predominate. However, once the final restrictions on carrying commercial traffic over the Internet ended in 1995 a combination of factors made the current Internet suite of SMTP, POP3 and IMAPemail protocols the standard (see Protocol Wars The term electronic mail has been in use with its modern meaning since 1975, and variations of the shorter E-mail have been in use since 1979:

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  email is now the common form, and recommended by style guides.[4][5] It is the form required by IETF Requests for Comments (RFC) and working groupsThis spelling also appears in most dictionaries.
  
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  e-mail is the form favored in edited published American English and British English writing as reflected in the Corpus of Contemporary American English data but is falling out of favor in some style guides.
  
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  E-mail is sometimes used The original usage in June 1979 occurred in the journal Electronics in reference to the United States Postal Serviceinitiative called E-COM, which was developed in the late 1970s and operated in the early 1980s.
  
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  Email is also used.
  
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  EMAIL was used by CompuServestarting in April 1981, which popularized the term.
  
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  EMail is a traditional form used in RFCs for the "Author's Address".
  

The service is often simply referred to as mail, and a single piece of electronic mail is called a message. The conventions for fields within emails—the “To,” “From,” “CC,” “BCC” etc.—began with RFC-680 in 1975
An Internet email consists of an envelopeand content the content consists of a header and a body.