题目：
The following data sufficiency problems consist of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of counterclockwise), you must indicate whether.
Is the triangle depicted above equilateral ？（） (Figure not necessarily drawn to scale.)
(1) x+y+z=180°
(2) y=z
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
答案：
参考答案：E
解析：
Statement (1) is true of any triangle, so it does not make this triangle equilateral. (2) states that the triangle is isosceles, but unless it can be proved or disproved that x=y or x=z, there is not sufficient data to determine whether the triangle is equilateral.
