[单选] An aircraft has indicated that he wants you to change course and follow him. You cannot comply because of an emergency on board. Which signal should you make?（）
A . Fire a red flare at night or a red smoke signal by day B . Send the Morse signal N by flashing light C . Make a round turn (360°) and resume course D . Make an S turn (hard right then hard left) and resume course
（可视）对讲门禁系统常见故障如何解决？
“6841汇划来账凭证连续打印”交易，一次打印份数最大值为（）。 3。 5。 10。 20。
因行政管理的需要，确需立即实施行政许可的，（）可以设定临时性的行政许可。 省级地方性法规。 省级政府规章。 省级食品药品监督管理局规范性文件。 较大的市政府规章。
A旅行社将一个旅游团委托给B旅行社操作，但只支付了成本80%的费用，B旅行社接团后，擅自减少了几个景点，导致游客不满，要求A旅行社赔偿损失，A社却称是B社的责任，要游客找B社解决。A社的说法对吗？为什么？
（可视）对讲门禁系统如何进行维护保养？
An aircraft has indicated that he wants you to change course and follow him. You cannot comply because of an emergency on board. Which signal should you make?（）
