Read the following SAT test question and then click on a button to select your answer.

　　If, the value ofcan be which of the following?

       .

　　.

　　.

　　(A) only

　　(B) only

　　(C) only

　　(D) and only

　　(E),, and

2013年9月10日SAT考试官方每日一题答案：D

解析：

Roman Numeral Answer Format

Roman Numeral : Can the value of be ?

You could test this answer by substituting for in the equation and seeing whether the result is true. But you can also reason this question out without substituting numbers:

If , then is a positive number, because any nonzero number squared is positive.

If , then is negative.

So is negative and is positive.

Therefore, cannot be .

Mark Roman numeral with an “F” for false.

Roman Numeral : Can the value of be ?

This is a very easy substitution to make:

Roman numeral is true, so mark it with a “T” for true.

Roman Numeral : Can the value of be ?

Substitute for :

If , then .

Also, .

Roman numeral is true, so mark it with a “T” for true.

Check the Answers:

You now know whether each of the Roman numeral statements is true or false:

is false.
is true.

is true.

Find the choice that says only and are true.

SAT真题类型：Critical Reading > Sentence Completions

　　Choose the word or set of words that, when inserted in the sentence, best fits the meaning of the sentence as a whole.

　　Eduardo Galeano’s novel consists of discrete vignettes, so the reader must supply the invisible ------- binding such apparently ------- parts.

　　(A) emotions . . impersonal

　　(B) interpretations . . somber

　　(C) descriptions . . related

　　(D) connections . . independent

　　(E) categories . . cohesive

2013年9月11日SAT考试官方每日一题答案：D

解析：The word “so” indicates that the sentence is a cause-and-effect statement: the second half of the sentence must describe the way readers must respond to a novel that “consists of discrete vignettes.” Inserting the terms in choice (D) into the sentence creates a logical cause-and-effect statement. If the novel is composed of “discrete,” or unconnected, episodes, then the reader must supply the “connections” that bind these apparently “independent” parts.