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tension; strain; nervousness; stress
tensions (between countries, groups, etc.)
tonus; muscle tone
初めての発表で緊張して声が震えていた。
I was so nervous at my first presentation that my voice was shaking.
国家間の緊張がここ数年で急速に高まっている。
Tensions between nations have been rising rapidly in recent years.
彼女は緊張すると手に汗をかくらしい。
Apparently she sweats on her hands when she's nervous.