(1) switch on, have on, put on, stick on, turn on均可表示打开电器，stick on为非正式用法。

• Switch/Have/Put/Turn/Stick the radio on , will you? I want to listen to the news.
  打开收音机，好吗？我想听听新闻。
• Please put the light on ; it's getting dark.
  请打开灯，天黑下来了。

 (2) be on可指“(电器)开着”，表状态，come on, go on也可指“(灯或其他电器)打开了”，是不及物用法，表示动作。come on表示“(电器)开始运作”；go on指“(电器)被打开”。

• I thought you were in when I saw that the light was on .
  当看到灯亮着时，我以为你在屋里。
• Just as I entered the building, all the lights came on .
  当我走进大楼时，所有的灯都亮了。
• The street lights go on when it gets dark, and go off at midnight.
  街灯在傍晚时分亮起，午夜时灭掉。

 (3) keep on, leave on可以表示“使电器保持工作状态”。

• There is no need for office buildings to keep/leave their lights on all night, when the government has asked everyone to save power.
  当政府号召每个人节约能源之时，办公大楼没有必要整夜亮着灯。

 (4) remain on, stay on, stop on均可指“电器继续停留在工作状态”，是不及物用法。

• When the lights remained/stayed on in his room long after his usual bedtime, I knew that something was wrong.
  当过了他正常睡觉的时间很久，而他屋里的灯还亮着时，我就意识到有什么地方不对劲。
• Something must be wrong, I switched the radio off but it stopped/stayed on .
  一定是出毛病了，我关上了收音机，可它还是响。

 (5) snap on可指“(突然)打开(电器)”。

• The policeman snapped the light on and caught the thief stealing the jewels.
  警察突然打开灯，抓住了那个正在盗窃珠宝的小偷。