下列哪项检查可以诊断子宫性闭经
A．垂体兴奋试验阴性B．孕激素试验阳性C．雌激素试验阳性D．雌孕激素序贯试验阴性E．孕激素试验阴性
参考答案：D
Before the economic crisis came John had sensed the firm was to be ruined and he _____ just in time.
A．pulled out
B．pulled off
C．pulled up
D．pulled down
何为雾沫夹带现象？
