1: Scientists claim that the discovery of the first authenticated mammal bones in amber could provide important clues of determining, in addition to how, when mammals colonized the islands of the West Indies.
A: of determining, in addition to how, when mammals colonized the islands of the West Indies
B: in the determination of how and when the islands of the West Indies were colonized by mammals
C: to determine how mammals colonized the islands of the West Indies and when they did
D: for determining when the islands of the West Indies were colonized by mammals and how they were
E: for determining how and when mammals colonized the islands of the West Indies


2: Although women's wages are improving, Department of Labor statistics show that the ratio of their earnings with that of men have been roughly static since 1960.

A: with that of men have been
B: to that of men are
C: to those of men have been
D: with those of men is
E: to those of men has been


3: In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought its western border within reach of the Pacific Ocean.

A: In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought
B: For about four cents an acre the United States acquired, in the Louisiana Purchase of 1803, 828,000 square miles, more than doubling the country's size and it brought
C: With the Louisiana Purchase in 1803, the United States acquired 828,000 square miles for about four cents an acre, more than doubling its size and bringing
D: The United States, in the Louisiana Purchase of 1803, for about four cents an acre, acquired 828,000 square miles, more than doubling the country's size, bringing
E: Acquiring 828,000 square miles in the Louisiana Purchase of 1803, the United States bought it for about four cents an acre, more than doubling the country's size and bringing

2: Although women's wages are improving, Department of Labor statistics show that the ratio of their earnings with that of men have been roughly static since 1960.

A: with that of men have been
B: to that of men are
C: to those of men have been
D: with those of men is
E: to those of men has been

ratio of X to Y is correct.
"since 1960" reminds us of present perfect tense. Since " ratio" is singular , thus present perfect must be " has been".
I'm left with E.

3: In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought its western border within reach of the Pacific Ocean.

A: In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought
B: For about four cents an acre the United States acquired, in the Louisiana Purchase of 1803, 828,000 square miles, more than doubling the country's size and it brought
C: With the Louisiana Purchase in 1803, the United States acquired 828,000 square miles for about four cents an acre, more than doubling its size and bringing
D: The United States, in the Louisiana Purchase of 1803, for about four cents an acre, acquired 828,000 square miles, more than doubling the country's size, bringing
E: Acquiring 828,000 square miles in the Louisiana Purchase of 1803, the United States bought it for about four cents an acre, more than doubling the country's size and bringing

There's no need to use "that" in A. It just made the sentence redundant.
B seems to lack the main verb and " it" in B is ambiguous.
E is redundant.
the positon of " for about four cents an acre" in D is not favored as it can be better if placed after " acquired 828,000 square miles"
C is concise and correct those mistakes of other choices.
Go for C.

1: Scientists claim that the discovery of the first authenticated mammal bones in amber could provide important clues of determining, in addition to how, when mammals colonized the islands of the West Indies.
A: of determining, in addition to how, when mammals colonized the islands of the West Indies
B: in the determination of how and when the islands of the West Indies were colonized by mammals
C: to determine how mammals colonized the islands of the West Indies and when they did
D: for determining when the islands of the West Indies were colonized by mammals and how they were
E: for determining how and when mammals colonized the islands of the West Indies


Got to be E. A and B is undiomatic. C and D is awkward. only E fits how and when properly.
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3: In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought its western border within reach of the Pacific Ocean.

A: In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought
B: For about four cents an acre the United States acquired, in the Louisiana Purchase of 1803, 828,000 square miles, more than doubling the country's size and it brought
C: With the Louisiana Purchase in 1803, the United States acquired 828,000 square miles for about four cents an acre, more than doubling its size and bringing
D: The United States, in the Louisiana Purchase of 1803, for about four cents an acre, acquired 828,000 square miles, more than doubling the country's size, bringing
E: Acquiring 828,000 square miles in the Louisiana Purchase of 1803, the United States bought it for about four cents an acre, more than doubling the country's size and bringing



Here I am stuck between C and D. Don't know which one to choose.
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hey ya......

Question 2

- ratio of A to B is correct. -> A and D are out.
- 'to that' is not correct -> B is out.
- ' have been' is wrong as ratio is not plural -> C is out.
- Think of these two sentences to see which one make sense to you:
1) The ratio of green balls to red balls is 2:1
2) The ratio of green balls to red balls are 2:1

E is the best choice.

E. provides ......for and the underlined part is direct and clear.

E. llism....

C. between A and C, C is better because "with the Louisiana Purchase in 1803" in C is much clearer than "in the Louisiana Purchase of 1803" in A. BDE are all have bad construction...