下列各数中，是不等式x﹣4≧2（x+2）的解的是[
A．4
B．﹣3
C．﹣5
D．﹣9
答案：D
若△ABC的三条边a，b，c满足关系式：a4+b2c2-a2c2-b4=0，则△ABC的形状是______．
Which of following statements about testing software with data is (are) true Ⅰ. The primary purpose of such testing is to find errors. Ⅱ. Such testing can demonstrate the existence of errors but can not demonstrate the absence of errors.
A．Neither
B．Ⅰ only
C．Ⅱ only
D．Ⅰ and Ⅱ
