A Grammatical Problem

(1) You cannot replace ‘killing' and 'injuring' with 'killed' and 'injured'’

Use of present participle:
I saw a policeman.
The policeman chased a thief. (active voice)

I saw a policeman chasing a thief.
(chasing ~ present participle; active participle)

An active participle after the main clause can express result.
They pumped waste into the river and killed all the fish.
They pumped waste into the river killing all the fish.
(killing ~ present participle; active participle)

Use of past participle:
I saw a thief.
The thief was chased by a policeman. (passive voice)

I saw a thief chased by a policeman.
(chased ~ past participle; passive participle)

They have not identified the body which was found in the river.
They have not identified the body found in the river.
(found ~ past participle; passive participle)

(2) 有一個 For 字, 這句子說明原因
For is a preposition. In this case “For” is used to show the reason or cause. For = 因為.
“in December 1982’ shows in what month of the year the accident happened.

If you delete the word “for”, your sentence simply states that the accident happened in December 1982.



2012-11-28 09:54:50 補充：
Other uses of participles:

You use present participle in continuous tense.
am,is,are/was, were/will be + verb-ing

You use past participle in perfect tense.
has/have/had/ will have + past participle

Besides, past participle is used in passive voice.

(1)present participle used in the phrase part in the sentence.
---eg:-killing and injuring vs crashed and slammed.
(2)referred to by December 1982=refer (v)
=Referring (gerund) December 1982.is the original meaning for "for in".