多用户对网络系统的最常见的压力测试方法为（）
A.负载测试
B.模拟访问
C.直接访问
D.可靠性测试
参考答案：B
Look, you can see many _________ in the pool. And here is some ________
for you to keep them.
A．fish; suggestion
B．fishes; advices
C．fish; advice
D．fishes; suggestions
下列对楔状缺损的描述，错误的是
A．为慢性缺损B．多发生在颊侧牙颈部C．多见于青少年牙的唇、颊面D．前磨牙多见E．一般有牙龈退缩
