最早将宇宙体系模型化的是哪个国家()
A、印度
B、埃及
C、希腊
D、中国
参考答案:C
根据句意和括号内所给词的提示填空。
1. The man can speak three ______ (language).
2. Linda ______ (pay) 20 yuan and takes the shoes home.
3. Our teachers are ______ (friend) to us.
4. The girl likes______ (sit) on the bed and watching TV.
5. We ______ (play) soccer at the weekend. What did you do?
离心泵密封部分包括()与泵壳接缝处的密封。
A、轴套
B、水封环
C、密封环
D、叶轮