若温度失控,应采取什么措施?
参考答案:检查温度传感器或燃烧器是否有故障;如果温度过高,则关闭手动阀,取下燃烧器,直至温度恢复到正常操作范围内。
She listens to the radio every day, ______? [ ]
A. doesn't she
B. isn't she
C. hasn't she
D. won't she
在关系数据库中,把数据表示成二维表,每一个二维表称为【 】。