would ring
had rung
has rung
was ringing
Answer is Right!
Answer is Wrong!
The correct answer is D. was ringing.
The sentence is in the past tense, so we need to use a past tense verb. The other options are not in the past tense.
A. would ring is in the future tense.
B. had rung is the past perfect tense.
C. has rung is the present perfect tense.
The telephone was ringing several times before I answered it. This means that the telephone was ringing at a time in the past before I answered it.