The phrase "a demonstration has been" is correct and usable in written English.
It can be used when discussing an event or action that has taken place in the past, particularly in a formal or academic context.
Example: "A demonstration has been conducted to showcase the new software features."
Alternatives: "a demonstration was held" or "a demonstration took place".
Even a single observation of a skill demonstration has been shown to be effective in enhancing performance of that skill [ 22].
A large demonstration has been called for Thursday.
A second demonstration has been called for 1 June.
A national demonstration has been planned for 29 January in Birmingham.
It remains to be seen if they will grow in the runup to July 8th, when a large demonstration has been called by several protest movements.
A golf demonstration has been scheduled at the Rocinha Sports Complex sponsored by HSBC bank, with support from the ministry of sport and the Professional Golf Association.
A public demonstration has been held, the co-owner of Novaya Gazeta, the newspaper where Politkovksaya had worked since 1999, is offering a 25 million ruble reward for information leading to the arrest of the culprit(s), the GOR Prosecutor General has taken personal charge of the investigation, and prominent media and political personalities have condemned the murder.
Following the Nakba Day protests by Palestinian refugees on the border with Lebanon and the fence between the Israeli-occupied Golan Heights and Syria, a similar demonstration has been called for this Sunday, June 5, to mark the anniversary of the Six Day War.
Nevertheless, unionists and labor supporters in Tucson and Phoenix have been protesting the legislation; Congressman Raul Grijalva has made public statements against the bills; MoveOn.org activists have created an online petition; the AFL-CIO is holding public hearings in Tucson and Phoenix; and a major demonstration has been planned for the state capitol on March 1.
The XT-ADS, an accelerator-driven system for an experimental demonstration, has been investigated in the framework of IP EUROTRANS FP6 project.
