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Answer:
↣ I have included a checkmark at the right of the sentences in order to mark them incomplete. I've also rewritten the sentences below. 
The typewriter on the table. ✓
 • The typewriter is on the table.
A secretarial career rewarding job. ✓
 • A secretarial career is a rewarding job.
Harry a great math student. ✓
 • Harry is a great math student.
Step-by-step explanation:
In order to form a proper sentence, it must include a subject, verb, and independent clause. Hence, it is necessary to add the linking verb "is" so that the sentence expresses a complete thought. 
. . • ☆ . ° . • °: . * ₊ ° . ☆
I hope this helps!
peachtea ^-^
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