Choose appropriate verb forms to fill in the blanks:I saw an accident last night. Somebody __________ (call) an ambulance butnobody ___________ (injure) so the ambulance __________ (not/need).

The sentence "I saw an accident last night. Somebody called (past simple) an ambulance but nobody was injured (past simple) so the ambulance wasn't needed (past simple)." describes a sequence of events that happened in the past.

1. The first action is "Somebody called (past simple) an ambulance." This is a straightforward past action.
2. The second action is "nobody was injured (past simple)" indicating the state or condition after the accident.
3. The third action is "the ambulance wasn't needed (past simple)" indicating the outcome of the situation.

Option B: called; was injured; wasn't needed accurately represents this sequence of events in the past tense.

In Option A, "had called" (past perfect) suggests that the action of calling happened before another past action, which is not the case here.
In Option C, "had called" is suitable for the first action, but "was injured" and "wasn't needed" do not accurately reflect the sequence of events.
In Option D, "had called" is suitable for the first action, but "injured" (past simple) does not accurately describe the state after the accident, and "was not needed" is a less natural phrasing compared to "wasn't needed."

The correct answer is Option B: called; was injured; wasn't needed, which accurately represents the sequence of events and maintains proper tense agreement.