How is variation indicated on a small-scale nautical chart?（）.
A. Magnetic compass table
B. Magnetic meridians
C. Isogonic lines
D. Variation is not indicated on small-scale nautical chart
Scuffed cylinder liner surfaces in a diesel engine can result form（）
A. starting the engine hot
B. knurling the piston skirt
C. operating an overheated engine
D. using scuff resistant piston ring
抽油机曲柄剪刀差过大排除加工精度有问题还有（）安装不合理。
A. 曲柄
B. 输入轴
C. 中间轴
D. 输出轴键
使用哪个命令可以将所有出现的“HELLO”替换为“hello”？
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