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I recently took this quiz and scored poorly. I was wondering if anyone could help me identify why these sentences have grammatical errors.

Thanks,


The apartment was up two rickety flights of stairs and it was the best they could afford.
Your Answer:
True INCORRECT
False CORRECT ANSWER
Points Received: 0 of 2
I assume this correct punctuation would be:
The apartment was up two rickety flights of stairs, and it was the best they could afford.

Although the teacher believed that it was important for her students to write every day she did not enjoy grading so many papers.
Your Answer:
True INCORRECT
False CORRECT ANSWER
Points Received: 0 of 2
I assume this correct punctuation would be:
Although the teacher believed that it was important for her students to write every day, she did not enjoy grading so many papers.

The teacher did not enjoy grading so many papers, although she believed that it was important for her students to write every day.
Your Answer:
True INCORRECT
False CORRECT ANSWER
Points Received: 0 of 2
I assume this correct punctuation would be:
The teacher did not enjoy grading so many papers; although, she believed that it was important for her students to write every day.

In the film a lawyer reopens an investigation on behalf of a woman imprisoned for murder, but she convincingly claims that she is innocent.
Your Answer:
True CORRECT ANSWER
False INCORRECT
Points Received: 0 of 2
I assume this correct punctuation would be:
In the film a lawyer reopens an investigation on behalf of a woman imprisoned for murder; but, she convincingly claims that she is innocent.

In the film a lawyer reopens an investigation on behalf of a woman imprisoned for murder; however, she convincingly claims that she is innocent.
Your Answer:
True CORRECT ANSWER
False INCORRECT
Points Received: 0 of 2
I assume this correct punctuation would be:
In the film a lawyer reopens an investigation on behalf of a woman imprisoned for murder; however, she convincingly claims that she is innocent. (This one has me stumped as it looks correct to me)

The community was unaware of the city's plan to tear down a playground, therefore, few citizens attended the city council meetings.
Your Answer:
True INCORRECT
False CORRECT ANSWER
Points Received: 0 of 2

Because the community was unaware of the city's plan to tear down a playground, few citizens attended the city council meetings.
Your Answer:
True CORRECT ANSWER
False INCORRECT
Points Received: 0 of 2
I assume this correct punctuation would be:
Because the community was unaware of the city's plan to tear down a playground; therefore, few citizens attended the city council meetings.

Scientists are currently interested in studying polar bears because the bears' body chemistry may reveal how pollution has affected the Arctic.
Your Answer:
True CORRECT ANSWER
False INCORRECT
Points Received: 0 of 2
I assume the correct punctuation would be:
Scientists are currently interested in studying polar bears, because the bears' body chemistry may reveal how pollution has affected the Arctic.

The police were warned to expect trouble and every available officer lined the street.
Your Answer:
True INCORRECT
False CORRECT ANSWER
Points Received: 0 of 2
I assume the correct punctuation would be:
The police were warned to expect trouble, and every available officer lined the street.