题目：
Which of the following is the single most reliable indicator of the existence and intensity of acute pain
A．The client's vital signs.
B．The client's self-report of pain.
C．The nurse's assessment of the client.
D．The severity of the condition causing the pain.
答案：
参考答案：B
解析：The client's self-report of pain is the single most reliable indicator of the amount of pain the client is experiencing. Pain tolerance and the expression of pain can vary a great deal among clients.
