修井机的技术参数主要取决于动力设备的()、零部件材料的性能、加工制造、设计方法等四大因素.
参考答案:功率和转速
情景交际。
A: Hello, Wang Lin!
B: Hi, Han Mei!
A: What are you doing (1)______vacation?
B: I don't (2)______. What about you?
A: I'm going to Huang Mountain. I think it's a beautiful place.
B: Yes. I (3)______there last year. Who are you going (4)______?
A: My parents. B: Have a good (5)______.
A: Thank you.
在基础琼脂培养基中不含有的营养成分是()
A.水解酪蛋白
B.牛肉膏
C.蛋白胨
D.NaCl
E.琼脂