Which auxiliary verb do I need to use the following sentence, is or are?

According to this anatomical position we decide what front or back is (or are), what right or left is (or are) in the body.

  • 1
    Can "front or back" be more than one thing?
    – user3169
    Nov 8, 2015 at 4:58
  • it depends how you look at this. I'm not English native speaker, that's why I'm here to ask who knows. There are languages that you can refer to such case as singular or plural. Nov 8, 2015 at 6:27
  • OK, then you mean the "front or back" of what? And what is "this position"? More information is needed so it is clear what you are asking..
    – user3169
    Nov 8, 2015 at 18:24
  • according to anatomical position we decide what is the front and back of the body. Nov 8, 2015 at 18:26
  • 1
    I don't have what to add. I really don't understand what the problem is. :( Nov 8, 2015 at 23:15

2 Answers 2


According to this anatomical position we decide what front or back is (or are), what right or left is (or are) in the body.

I think this sentence has a few problems. Maybe this is better:

According to this anatomical position in the body, we decide which directions are front, back, left, and right.

1) "what front or back are" is a confusing statement. Why not say "Which directions are ..." ? Here "are" modifies the directions so you avoid the problem you had by listing the directions, and "are" modifies "directions," so it is plural. And quite honestly I'm not sure what the answer is in the given form, it is a strange sentence.

2) I think another problem is "and/or". We can say "which directions are front and back" or "which directions are front or back." This is confusing because we can't have one direction be both "front and back", so I think or works by saying it is either "front or back" In your sentence, since the verb "is" modifies the "front" and "back", that problem is worse. So "or" is more appropriate here.

However, I think it is much better to use "and" if we list all four directions together, because then we are completing the list. I am a bit unsure of this so comment your thoughts, but "or" seems innappropriate in the example I am giving. Ask, "what are the directions?" They are a list of prepositions "front, back, left, and right." The problem I have is that it sounds as though we listing directions, instead of saying which direction is which, but that is implied by "we decide."

3) "According to this anatomical position ... in the body." Stripping out the middle makes the sentence much easier to understand what the "anatomical position" is - a view of the body. This calls for the phrases to be reordered, so that "body" is closer to "anatomical position."


Keeping it simple: 'According to this anatomical position we decide which is front or back; which is right or left in the body.'

Note: we use WHICH because we want to choose between a few choices, like which gender the body was.

Your friend offers you four pens and says, "Which colour pen?" because there are a few well-understood choices. We would use WHAT in other cases, eg if we wanted to decide 'what colour' the skin was, because there are infinite colours to consider; or "what is in that bottle?" - we don't know what it might be.

Some cases are not critical ie we could ask 'what nationality', or 'which nationality' without worrying. The important thing is to use 'which' if we know simply what the exact choices are, and want to point to one or more of them.

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