You almost answered your own question when you wrote: ?strong>What
is the best way to explain??What is used to ask a
question when there are an unknown number or infinite possibilities
for an answer. You know that there are many, many ways that exist to
address your question, and you want to find out—from all those
possibilities that you might not even know about—what the best
way is.
(In “What is the best way to explain…?,” what
is a question word. In your question about shoes, what
and which are determiners used before nouns –
“shoes,” in this case.)
In answer to your question about shoes, you would most likely ask what
color, not which color, if you haven抰 seen
the shoes yet and you want the owner of the shoes to tell you the color.
This is because there are so many possibilities that
the color of the shoes could be.
But, you would probably use which color if you are
choosing between two items, already defined, in a different sentence,
like this:
|
(a)
|
Which color shoes should I wear with
this dress—blue or black?
|
|
(b)
|
Which shoes should I wear with this dress—my
blue ones or my black ones?
|
You can use which when you have a very small or limited
field to choose from. Certainly use which, not what,
when there are only two choices, or if both speaker and listener can
visualize all the items under consideration:
|
(c)
|
Which foot did you break?
|
|
(d)
|
Which one of your sisters is the singer?
|
|
(e)
|
Which of the restaurants is open on Sunday?
|
Similarly:
|
(f)
|
Which movie do you want to see?
|
Sentence (f) asks for information about the time or theater or title
of a movie when you are selecting from only a few choices, known to
both the speaker and listener: perhaps the time (4:45 p.m., 7:30 p.m.,
or 10:00 p.m.), or the theater (the Plaza Theater, the Cinemaplex, or
the AMC theaters), or the movies that are playing in town. If you don抰
have any idea of how many movies there are in the discussion you are
having, if you are thinking of all the possible movies, you would say:
|
(g)
|
What movie did you see last night?
|
|
(h)
|
What was Anthony Quinn抯 last film?
|
Often, either which or what can be
used for several choices, depending on what is in the speaker抯 mind:
|
(i)
|
Which bus goes downtown?
|
|
(j)
|
What bus shall I take?
|
Both sentences are fine. The speaker is probably thinking about fewer
buses in sentence (i) than in sentence (j). Similarly,
|
(k)
|
Which country in Europe is he from?
|
|
(l)
|
What country in Europe is he from?
|
are both OK.
However, you would probably want to say
|
(m)
|
What country is he from?
|
when you are not limited to one area because there are many, many choices
of countries in the world, and probably more countries than you know
of. You抎 also say:
|
(n)
|
What language does he speak?
|
because there are so many languages in the world, and you don抰 know
what all of them are.
However, you could very well say
|
(0)
|
Which language does he speak?
|
if, for example, his mother speaks French, his father speaks Italian,
and the family lives in Brazil—in this case, there are only three
clear possibilities.