A – specific: Referring to One in Particular

A - SPECIFIC	A - UNSPECIFIC
Use "a" to refer to one you observe or have knowledge about.	Use "a" to talk about one in general (one as an example of all; true of all comets).
A comet was seen in the western sky last night. (first mention)	A comet appears to have a tail as it streaks through the sky.
The comet was believed to be Hale-Bopp.	A comet also has a dense head.
The comet has a spectacular, bright tail.	If you look up in the sky, you might see a comet.

#	YOUR RESPONSE	FEEDBACK
1.	A black hole is an object, typically a collapsed star whose gravity is so strong that its escape velocity exceeds the speed of light. Since nothing is known to exceed the speed of light, nothing can escape from a black hole. Does a black hole refer to any black hole? Does a black hole refer to a particular black hole?	Answer 1
2.	A planet was later discovered farther out in the solar system. The planet, Jupiter, named after the Roman god, was the largest of all. Does a planet refer to any planet? Does a planet refer to a particular planet?	Answer 2

#	YOUR RESPONSE	ANSWER
3.	People did not always know what a comet was. In ancient times, people thought comets were "power rays" of super- natural beings. specific unspecific	Answer 3
4.	They thought a comet contained fire because they are so bright in the sky. specific unspecific	Answer 4
5.	Some people in ancient times thought that a comet was a curse. To save himself from "the curse of the comet," Emperor Nero of Rome had all possible successors to his throne executed specific unspecific	Answer 5
6.	In 1910, people panicked when a comet passed through Earth's path around the Sun. specific unspecific	Answer 6
7.	In Chicago, people sealed their windows to protect themselves from a comet that they believed had a poisonous tail. Others committed suicide. Special "Comet Protecting Umbrellas," gas masks, and "anti-comet pills" were sold. specific unspecific	Answer 7
8.	Not everyone saw a comet as bad luck. Some thought they brought good luck. specific unspecific	Answer 8
9.	They also believed that a comet carried angels through the heavens. specific unspecific	Answer 9

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