briefing       
noun [ C or U ] uk/ˈbriː.fɪŋ/ us/ˈbriː.fɪŋ/
 简报,简要介绍;简明指示;情况介绍会
information that is given to someone just before they do something, or a meeting where this happens
  They received thorough briefing before they left the country. 在离开该国之前,他们得到了详细的指示。 
 We had to attend a briefing once a month. 我们每月必须参加一次情况介绍会。