CNN News:美国两党大会因疫情线上举行 正式提名总统候选人

And this is the first time that virtual political conventions are largely replacing physical ones. Conventions are where America's major political parties formally nominate their candidates for president and where they define their party platforms, what they stand for and what they plan to do ahead of the presidential elections.

Traditionally the party that doesn't hold the White House has its convention first. And the 2020 Democratic National Convention starts Monday and runs through Thursday. These meetings will be mostly virtual except for a small gathering of delegates in Milwaukee, Wisconsin and will nominate former Vice-President Joe Biden for the presidency. The 2020 Republican National Convention will meet next week from Monday through Thursday. These meetings will also be largely virtual except for a scaled down event in Charlotte, North Carolina and will nominate incumbent President Donald Trump for a second presidential term. These unusual online events in an unusual year will be a test of technology and for the parties to galvanize voter support when they're not gathering by the thousands in person.