导线当它第一次受到拉力以后,发生的塑性变形叫初伸长。初伸长使得导线的:()
A、实际长度增加;
B、弛度增大;
C、应力相应减大;
D、应力相应减小。
参考答案:A, B, D
人工后牙半解剖式牙尖斜度为()
A.0°
B.10°
C.20°
D.30°
E.40°
翻译以下短语并完成句子
1.turn to sb. for help ____
2. turn to Page 20____
3. turn to the English dictionary _____
4. He often____me when he is in trouble.
当他遇上麻烦时常常向我求助.
5. After he left the university he became a teacher, but later ____ joumalism
大学毕业后,他当了老师,但后来转向了新闻业.
6. Their talk____the change that had taken place in the city.
他们的话题转到城市发生的变化.