<p>(were they to be told) the purpose. of the study, the participants might find it difficult to answer the questions
spontaneously.<br>
i choose (by telling them) and the sentence is correct as it is </p>
<p>i dont understand why my answer is wrong and why the sentence is ok as it is. were is past and after the comma is present</p>
<p>“By telling them” is a modifier and must be followed by someone who is telling them or it will produce a modifier error. This is a correct use of that phrase:
“By telling them the purpose of the study, researchers might make it difficult for the participants to answer the questions spontaneously.”</p>
<p>“Were they to be told” is subjunctive/conditional and means the same thing as “If they were told” or “If they were to be told.”</p>
<p>thx for the second time i think i get it now. it was something i always had trouble with</p>