当主要动作的语义牵涉到另一个时、空、人物都可独立的事件,就要以子句作为补语
He thinks that … → He thinks that is will rain tomorrow.
英文“说、想、以为”等沟通认知动词的后面都要搭配名词子句,表达认知或沟通的内容。子句代表另一个独立事件,时间、地点、人物都可能和主要子句不同。补语标记that用来区隔这两个事件,引导子句补语,补充说明“说、想”必然牵涉到的内容:
I think that he will come tomorrow.
I think that he came back last week.
我此刻“想”的事可能在过去或未来发生,因此“说、想”的内容就可以天马行空,人、地、时都自成一格。
此外,that-子句还可作为事实、理论、想法等名词的补语,补充说明名词的具体细节:
The fact [that global warming is affecting many parts of the world] has been addressed by scientists. → 说明主词
Scientists have addressed the fact [that global warming is affecting many parts of the world]. → 说明受词
必须特别提醒:子句补语的标记that,虽然在动词后可以省略,但放在名词后作补语时,就不能省略,一定要加that,作为名词和名词子句间的明显区隔。若是少了that,就造成两个名词并排站立,语义关系不清:
The fact global warming is affecting the world. → (×),无法理解
I think global warming is affecting the world. → (√),无伤理解
由此可见,补语的形式和功能,也要从沟通的角度来理解。基于形、义搭配的原则(form-to-meaning),每一种形式都各自有其形式所代表的意涵。
——劉美君. (2012). 英文文法有道理! 重新認識英文文法觀念. 聯經.