Definition: In each example you will read a short sentence (or two). Then, a pronoun in the text is mentioned. Your task is to choose a referent which the mentioned pronoun refers to. You will be given two options in each case and one choice should seem much more likely to you than the other.

Positive Example 1 -
Input: sentence: I couldn't put the saucepan on the rack because it was too tall .pronoun: it. A) the saucepan B) the rack
Output: the rack

Positive Example 2 -
Input: sentence: Arnold greatly influenced Jackson , though he lived two centuries earlier .pronoun: he. A) jackson B) arnold
Output: arnold

Negative Example 1 -
Input: sentence: Joe and David's uncles can still beat them at tennis , even though they are 30 years younger .pronoun: they. A) joe and david B) joe and david's uncles
Output: joe and david's uncles

Negative Example 2 -
Input: sentence: gaston passed the half-empty plate to hershel because he was full .pronoun: he. A) Gaston B) hershel
Output: hershel

Now complete the following example -
Input: sentence: the biologists are studying three species of aquatic vertebrates that have recently been found living in the indian ocean . they appeared two years ago .pronoun: they. A) the biologists B) the aquatic vertebrate
Output: 


Output: the aquatic vertebrate