為何有兩個動詞

The grammar rule of "one verb only" is for a sentence that doesn't contain a clause. For a sentence with one or more clauses, each clause has its own verb

In your example, there is an omitted "that" which heads up a "noun clause" right after the verb "discovered".

The sentence contains 3 parts:
Subject: Regulators looking into the issue
Verb: discovered
Object: [that] a cable for controlling the cooling system had mistakenly been removed.

The object is a sub-ordinated clause headed by the omitted relative pronoun "that". Within that sub-ordianted clause, "a cable controlling the cooling system" is the subject, and "had mistakenly been removed" is the intransitive verb in passive voice.

Therefore, "discovered" is the verb for the main clause, and "had been removed" is the verb for the subordianted clause, and grammar rule allows each clause to have a verb, so 2 verbs for 2 clauses.



2011-03-27 21:18:36 補充：
The 4th paragraph should be:
The object is a sub-ordinated clause headed by the omitted relative pronoun "that". Within that sub-ordianted clause, "a cable controlling the cooling system" is the subject, and "had been removed" is the intransitive verb in passive voice, "mistakenly" is the adverb.

因為有兩個clause,
可以咁睇

Regulators looking into the issue discovered a cable for controlling the cooling system had mistakenly been removed.
轉為
Regulators who looked into the issue discovered a cable for controlling the cooling system had mistakenly been removed.

在報章上看到,
Regulators looking into the issue discovered a cable for controlling the cooling system had mistakenly been removed.

= it can be rewritten as

Regulators looking into the issue discovered a cable for controlling the cooling system, which had mistakenly been removed.


This is a complex sentence so it has two verbs.

發問者 : Regulators...discovered that a cable ...removed.