单项选择题 A、偶函数，无界 B、非奇非偶函数，无界 C、奇函数，无界 D、奇函数，有界

多项选择题 Why did Mr. Long Yongtu get so angry? A.He thought the US negotiator was unfriendly to him. B.He thought the US negotiator insulted the Chinese people. C.He thought the US negotiator questioned the quality of Chinese pork. D.He thought the US negotiator rejected the agreement in a rude way.

单项选择题 在进行具有火灾爆炸危险的实验时引发火灾，属于生产操作不慎引发的火灾。 A、正确 B、错误