Classes of Questions (values for temporal complexity type attribute)

This classification is based on the ways questions signal their time
dependence and on how straightforward it is to determine what time
information needs to be understood from a question in order to be able
to provide a suitable answer.

Almost all examples are from the Excite question log, with some minor
editing. Time expressions that are TIMEX2 markables are enclosed in
curly braces.

The classes are ordered according to a notion of simplicity in terms
of how superficially apparent it is that the question has a time
dependency.

1. "When" question. TML relation between a ?when? question word or
   phrase (?when??, ?what time??, ?{in} what year??, ?how long??,
   etc.) and the question focus. 
a. A TIMEX2 is the question focus.
i. When is {Ramadan}? (in general)
ii. When was {the first day of winter 1999}?
iii. When is {Ramadan} {this year}? (This question also falls in class
   3.)
iv. What is {the last day to contribute to a Roth IRA for {1999}}?
   (This question also falls in class 3.)

b. Something other than a TIMEX2 is the question focus. 
i. ON WHAT DATE DID THE CHALLENGER SPACE SHUTTLE EXPLODE?
ii. When did the Challenger explosion happen?
iii. What date is the AFC Championship Game on?
iv. What year was the toilet invented in?
v. How often do you feed a pet gerbil?
vi. How long do I cook a sweet potato?
vii. What is the life of four AA batteries?
viii. WHAT YEAR WAS IT WHEN THE KANSAS-NEBRASKA ACT ALLOWED FOR THE
SPREAD OF SLAVERY? (Note: ?What year was it when...? is treated here
as synonym for ?in what year did...?.)
ix. When does {the new millennium} begin? (This question also falls in
class 3.)
x. What time does the {winter} solstice occur for {1999}? Note: Not
sure if ?the winter solstice? should be considered a TIMEX2
markable. (This question also falls in class 3.)
xi. When is the next full moon? (This question also falls in class 3.)

2. Question focus is an expression of time or chronology. The question
   does not seek a time as a response, but rather a sequence or set of
   events. 
a. A time expression serves as the question focus. The time expression
   acts semantically as postmodifier of a head such as ?the events
   {of}?.
i. Do you have anything on {the decade from {1940} to {1950}}?
ii. Do you know anything about {the years 1720}-{1729}}? 
iii. Tell me about 1950.

b. A term such as "history" or "biography" serves as head of the
question focus. See later class re questions such as "Who is/was ?".
i. What do you know about the history of Castle Garden?
ii. Tell me more about Roman History.

3. Question focus NP is constrained by a modifying time term or
   phrase. The question focus is in the form of an NP. A prenominal or
   postnominal modifier provides temporal attributes for the question
   focus, anchoring the question temporally. No other temporal
   analysis of the question may be necessary. Note that some of these
   questions would be classified as time-dependent even without the
   temporal modifier -- classes 5 and 6.
a. The modifier is a TIMEX2 (plus leading preposition). The prenominal
   modifier or head of postnominal PP is a TIMEX2 markable, which
   anchors the qestion temporally in an absolute way. 
i. Where can I find {40's} music I can download on my computer free?
ii. Who is the {current} leader of China?
iii. Where can I find information on {medieval} life in a castle?
   (Note: This is phrased in the log as Where can I find information
   on life in a {medieval} castle?)
iv. How is baseball {today} different from baseball {years ago}?
v. What are some of the expected technological advancements of {the
   next century}?
vi. Where can I find the major events of the world during {the 1990s}?
vii. What are some of the greatest achievements from {the years 1000}
   to {2000}?

b. The modifier is a sequencing term. A sequencing term appears as a
premodifier of the question focus, anchoring it temporally in a
relative way. Sequencing terms include ?first?, ?initial?, etc.
i. Who won the first Rose Bowl game?
ii. Where can I find information about the first man on the moon?
iii. Who was the second president of the United States?
iv. Where can I find the latest United Mine Workers contract?
v. What was Pierre de Fermat's last theorem?

4. Question focus clause is constrained by a modifying time
   expression. TML relation between clausal predicate and the time
   expression.
a. The modifier is a TIMEX2 (plus leading preposition).
i. How many servings of Coca-Cola were consumed in {1994}?
ii. What happened on {Easter}?
iii. Who was born on {the 18th of December}?
iv. What was food like in {the 1400s}? 
v. How can I find how many seconds have elapsed since {1970}?
vi. What are some activities adult can play at {Christmas}?

b. The modifier is a phrase, but not a TIMEX2. Time expression is
anchored by something other than a TIMEX2 markable.
i. What kinds of weapons were used during the American revolutionary
war?
ii. Is it better to eat before or after a workout?

c. The modifier is a tensed temporal clause in the form of an indirect
question. The dependent clause could be processed as a "when"
question, and its answer used in processing the overall question. See
later class re cases where the modifying clause expresses more of a
condition than a time.
i. How old was Jackie Robinson when he died? (First answer the
question, "When did Jackie Robinson die?")
ii. Who was the ruler of Egypt when Jesus Christ was born? (First
answer, "When was Jesus Christ born?")
iii. How was abortion performed before it was legalized? (First
answer, "When was abortion legalized?")

d. The modifier is a reduced temporal clause in the form of an
indirect question. See later class re cases where the modifying clause
expresses more of a condition than a time.
i. What president had two vice-presidents die while in office? (First
answer, "When was each president in office?" ???)

e. The modifying clause is a tensed clause that states a temporal
ordering relation to the main clause.
i. What must happen before the {Christmas} feast can begin in Poland?
ii. Does cider vinegar have to be refrigerated after it has been
opened?
iii. Why do people have to stand when court starts? 
iv. Where can I find a keychain that beeps or chirps when I clap my
hands?
v. Do all saints' bodies not decompose after they die?
vi. How do I disable my modem speaker so it won't make that awful
noise when I connect to an online site?

f. The modifying clause is a reduced clause that states a temporal
relation to the main clause.
i. What are my payment options when shopping online?

5. The lexical semantics of the question focus NP or one of its
   modifiers signals a time dependency.
a. A superlative adjective that modifies the question focus NP signals
   the time dependency. 
i. Where can I find the cheapest minidisc player/recorder? 
ii. What is the fastest car you can buy?
iii. Where can I find information on the newest cellular phones?
iv. What are the most popular hair styles?

b. The head of the question focus NP signals the time dependency.
i. What is the population of Griffin, Georgia?
ii. What is the weather in Ellicotville, NY? (First reading of this
seems to be time dependent.)
iii. WHO IS THE PRESIDENT OF VENEZUELA?
iv. How much francium is there in the world? (Does this Q belong in a
different class?)

6. The semantics of the question focus clause signals a time
   dependency. 
a. The question asks for information about who is/was a person. The
   tense may signal whether the person is still alive or not, which
   could help in disambiguating name homonyms.
i. Who was Johann Carl Friedrich Gauss?
ii. Who is Britney Spears?

b. The lexical semantics of the predicate indicate time dependence. 
i. How much do dental assistants make?
ii. How much is the Death of Superman comic book worth?
iii. What company is ranked number 1 on the fortune 500 list of
companies?