- it can be used for future reference
<span>- it can be used as the proof of work for the boss</span>
For the answer to the question above, I believe it is various forms of be.
The most common linking verbs are, am, is, are, was, were, being, and been, so the correct answer is the third choice among the given questions.
I think the answer is D
Not too sure just what I think
Hope that helps a little
