一般他励直流电动机在额定励磁状态时,磁路已接近饱和。()
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What are the people with infected ears advised to do？
A. Use earplugs.
B. Eat a hard sweet.
C. Travel another day.
D. Ask for help from cabin crews.
According to the article, what causes ear discomfort while flying？
A change in air pressure.
B. A change in drinks.
C. A change in plane speed.
D. A change in temperature.
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