tour de force的用法和樣例：
例句
用作名詞 (n.)
- Work is equal to force times the distance through which the force acts.
功等於力乘上力作用所通過的距離。 - Until then, physicists had postulated boundary conditions in which no force acted on the ends of the strings, leaving them free to flap around.
當時，物理學家早已假定了沒有力作用在弦兩端的邊界條件，讓弦的末端可以自由擺動。
