一、Event Definition

ACE：an “event“ is defined as a specific occurrence of something that happens, often a change of state, involving participants (LDC, 2005B).
TimeML：“events” are characterized as “situations that happen or occur”

ECB+数据集对上述定义做了拓展，将来源于新闻语料中的事件定义为4个组件的组合

action：describing what happens or holds true
time slot：describing when something happens or holds true
location：specifying where something happens or holds true
participant ： gives the answer to the question: who or what is
involved with, undergoes change as result of, or facilitates an event or a state. We
divide event participants into human participants (viz. §2.2.3.3) and non-human
participants

ECB+数据集在标注数据集时是以事件为中心。

二、Action Component Annotation

2.1 Mention part of speech

动词（verb）
名词（noun）：包括普通名词（nominalization）和专有名词（proper noun），例如“The Civil War ended back in 1865.”，“Fast economic growth across the African continent”。
动词的现在分词或过去分词用作定语（attributive use of present- and past- participles in modifier position）。例如“The deceased mens’ house was sold yesterday”，“The crying baby had a high fever.”
形容词，代词或名词表示的谓语短语（predicative phrases expressed by adjectives, pronouns or nouns）。例如Game Five hero David Ross was happy just to be here.
代词（pronoun）。例如“A small earthquake has hit Japan’s eastern coast yesterday. It did not trigger a tsunami.”

2.2 Action Classes

ECB+数据集在标注action时，也对action的类别进行了标注。其中5种类别来TimeML，具体包括：OCCURRENCE, PERCEPTION, REPORTING, ASPECTUAL 和 STATE。除此之外，还另外标注了两种类型：ACTION_CAUSATIVE和ACTION_GENERIC。

OCCURRENCE：适用于新闻中的大多数动作，用于描述事情的发生。
PERCEPTION：描述与感知相关的动作，例如see, hear, listen等。
ACTION_REPORTING：用于组织或个人宣称、宣告某些事情，例如say, report, tell等。
ACTION_ASPECTUAL：描述历史事件的不同方面，例如begin，finish，stop，continue等。
ACTION_STATE：描述某物获得或真实的情况，例如hope，love，live，peace等。
ACTION_CAUSATIVE：描述与因果相关的动词提及，例如cause, lead to, result, facilitate, induce, produce, bring about。
ACTION_GENERIC：描述未指明时间地点的泛指事件。