In 1967, astrophysicist Jocelyn Bell Burnell noticed a series of anomalies in the data from a newly constructed radio telescope. While analyzing the chart recorder prints, she observed a tiny, repeating signal that pulsed with remarkable regularity. Although some of her colleagues initially dismissed the pulses as man-made interference, Bell Burnell remained convinced of their extraterrestrial origin. Her persistent investigation eventually leads to the discovery of pulsars, rapidly rotating neutron stars that emit beams of electromagnetic radiation. Today, astronomers use these celestial objects as precise cosmic clocks to study gravitational waves.
Which choice, if any, is the most appropriate replacement for the underlined word?
- ANO CHANGE
- ledAnswer
- Chas led
- Dis leading
Answer
The past tense verb 'led' is correct because it maintains consistency with the simple past tense verbs used to describe the historical events of 1967.
The passage describes a sequence of completed historical events that occurred in 1967, as established by the verbs 'noticed,' 'observed,' 'dismissed,' and 'remained.' The past tense verb 'led' maintains this historical timeframe. Although the passage transitions to the present tense in the final sentence ('Today, astronomers use...'), the action of the investigation resulting in the discovery is a past completed event and must remain in the simple past tense.
Step-by-Step Solution
Key Concept
Verb Tense and Consistency
Estimated Time:1m 0s