Write the correct relative pronoun (who, which, that, whose, where) to complete the following sentence:

Antibody tests can distinguish between infected birds and those ___ have simply been vaccinated.

Choose the modal auxiliary which best completes the sentence:

The authorities ___ clamp down on domestic violence. Things would be much better around here if they did.

Write the correct relative pronoun (who, which, that, whose, where) to complete the following sentence:

Tom Brokaw, ___ has been a veteran TV newsman with NBC News for over 20 years, has just been diagnosed with cancer.

Write the correct relative pronoun (who, which, that, whose, where) to complete the following sentence:

The nursing school ___ Dory learnt her trade has since closed down.