各位大侠求解释啊 完全不知道为什么选C Any medical test will sometimes fail to detect a condition when it is present and indicate that there is one when it is not. B) when a condition is present and indicate that there is one C) a condition when it is present and indicate that it is present D) when a condition is present and indicate its presence E) the presence of a condition when it is there and indicate its presence