No, I don't think formal clothes are always necessary at work. Many places now let you wear casual clothes because it's more comfortable, and when people are comfortable, they can work better.
不,我不認為在工作時總是需要正式服裝。現在很多地方都讓你穿便服,因為這樣更舒適,而當人們感到舒適時,他們可以工作得更好。