Rarely ______ such an extraordinary display of the aurora borealis at mid-latitudes.

Answer and explanation

Correct answer: C. do observers witness

Negative adverb 'Rarely' at clause head requires subject-auxiliary inversion: Rarely + do (aux) + observers (S) + witness (V).

Practise more Sentence Structure, Clause Types, and Error Identification.

Free questions with an explanation for every one, and full timed TOEFL ITP Indonesia mock tests.