宣布活动开始英语

open，adj. 公开的；敞开的；空旷的；坦率的；营业着的vi. 开始；展现vt. 公开；打开n. 公开；空旷；户外。过去式 opened过去分词 opened现在分词 opening第三人称单数 opens。例如：The automatic doors slid open. 自动门慢慢开了。Is the museum open on Sundays? 博物馆每星期天都开放吗？I declare this festival open. 我宣布庆祝活动开始。The door had been forced open. 门被强行打开了。We had to smash the door open. 我们只得用力把门撞开。She made haste to open the door. 她急忙打开门。She sleeps with the window open. 她爱开着窗户睡觉。Shall I open another bottle? 要不要我再开一瓶？I'll hold the door open for you. 我会把门给你开着的。Please, sir, can I open a window? 老师，请允许我打开一扇窗户好吗？The pool is open from 7 a.m. onwards. 游泳池从早上7点起开放。The door was wide open. 门四敞大开。The door burst open. 门突然开了。Open a window, it's like an oven in here! 打开窗户。这儿热得像火炉！The bag burst open and everything fell out. 袋子爆开了，里边的东西都散落出来。The park is now open to the public. 那公园现在对公众开放了。A log fire roared in the open hearth. 柴火在敞开着的壁炉里熊熊燃烧。The park is open during (the) daytime. 这个公园日间开放。The door creaked open. 门嘎吱一声开了。

Let's invite the judge to declare the competition start.

Now let's invite the jury to announce the beginning of the competition. 开头加一个Now，这样更加符合英语的表达习惯。

Now the competition begins!

Let the judge to announce the beginning of the competition.

Ladies and gentlemen: The competiotion starts now... here we go!