1) "I am filled with sadness."

Can you explain the grammar rules for using "filled" instead of fill?

2)"We visited the Detainees (sic) camps and we saw the jails." What does '(sic)' mean?

3) Sometimes we see 'p.s.' at the end of a letter. What does it mean?

1. The verb "am filled" is the passive form of "fill" in this sentence.

http://grammar.ccc.commnet.edu/grammar/passive.htm
Scroll down to the chart called Passive Verb Formation, and you'll see that all tenses in passive are formed by using the past participle form of a verb plus an auxiliary verb (form of the verb "to be").

2. To indicate an error in quoted material:
http://www.protrainco.com/essays/usage.htm
Scroll down to Sic? Sic! Sic!

3. The abbreviation PS or P.S. (note that the letters should be capitalized) stands for the Latin post script:
http://en.wikipedia.org/wiki/P.s

1) The use of "filled" instead of "fill" in the sentence "I am filled with sadness" is an example of using the past participle form of the verb "fill" to describe a state or condition. In this case, "filled" is used to indicate that the subject (in this case, "I") is completely experiencing the state of being filled with sadness. This construction emphasizes the level of intensity or extent of the feeling or condition.

To understand the grammar rules behind this usage, it's helpful to understand the concept of past participles. In English, the past participle form of a verb is often used to form the perfect tenses (such as the present perfect or past perfect) or as an adjective to describe a state resulting from the action of the verb. In this case, "filled" is functioning as an adjective modifying the subject "I."

To form the past participle of regular verbs, you typically add "-ed" to the base form of the verb. However, some irregular verbs have different past participle forms (e.g., "go" becomes "gone" instead of "goed"). In the case of "fill," the base form and past participle form are the same, but the use of "filled" in this sentence indicates the present state resulting from the action of filling something with sadness.

2) The term "(sic)" is used in writing to indicate that an error or mistake in a quotation has been transcribed or quoted exactly as it appeared in the original source. It is placed after the mistake, enclosed in parentheses, and is derived from the Latin word "sic," which means "thus" or "so."

By including "(sic)" after a mistake, the writer is signaling that they are aware of the error but have retained it intentionally to maintain accuracy or to highlight the original author's error. It is often used to avoid confusion or to prevent readers from assuming that the error was made in the transcription.

In the given sentence, the use of "(sic)" after "Detainees" indicates that the word was misspelled or used incorrectly in the original source, but it has been included as it appeared.

3) The abbreviation "p.s." stands for "postscript." It is often used at the end of a letter or other written correspondence to add an additional thought, message, or piece of information that was forgotten or deemed important to include after the main body of the text was already written.

Using "p.s." allows the writer to append this additional content as an afterthought, separate from the main body of the letter. It can be used to convey something significant that the writer wants to mention or to include an unrelated message that doesn't fit with the flow of the letter's main content.

The use of "p.s." is derived from the Latin phrase "post scriptum," which means "written after."