问题
单项选择题
某井发生卡钻事故时，查钻井手册可知，本井所用127mm钻杆的计算系数K＝715，经实验，几次拉伸钻杆伸长的总和△L＝20cm，所需的拉力差总和T=98kN，经计算，该井卡点以上钻杆长度L＝（）。
A.715m
B.1000m
C.1430m
D.2145m
答案
参考答案：C
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某井发生卡钻事故时，查钻井手册可知，本井所用127mm钻杆的计算系数K＝715，经实验，几次拉伸钻杆伸长的总和△L＝20cm，所需的拉力差总和T=98kN，经计算，该井卡点以上钻杆长度L＝（）。
A.715m
B.1000m
C.1430m
D.2145m
参考答案：C
| 下列每句的画线部分中有一处错误，找出并改正 。 | |
| ( )1. For many teenagers, Du Fei has a few habits that are not so good for him. A B C ( )2. I would rather go out than to stay at home. A B C ( )3. Exercising helps teenagers to stay health. A B C ( )4. He finded it important to learn English well. A B C ( )5. His teachers want him change his attitude. A B C | _________ _________ _________ _________ _________ |