单项选择题 美国有史一来的最大的航母是()

未知题型 What does the author say about meat and poultry?A．Organic meat and poultry is hardly available.B．A great amount of meat is consumed every year.C．They may contain antibiotics and growth hormones.D．Merciless killing of the animals lowers their quality.

判断题 虽然二因素方差分析中涉及三个假设检验，但是一定要使用同一个显著性水平。()