车床精车外圆的圆度误差与()。
A.长度无关
B.长度有关
C.直径有关
参考答案:A
用括号内所给动词的适当形式填空。
1. My father _____ (not listen) to the radio at the moment.
2. Tom _____ (write) a letter to his friend these days.
3. —What's your brother doing?
—He _____ (clean) his new car.
4. Let's _____ (shop) for the coming New Year.
5. What can you _____ (see) in the picture?
世界上最主要的混合农业是[ ]
A、蔗、果、桑、鱼混合农业
B、水稻与牲畜混合农业
C、谷物与牲畜混合农业
D、种植小麦与牧羊混合农业