Helen: Also, can they be used in formal occasions?

还有这两个词适不适合在正式场合下使用呢？

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Fig1. Emails prevail now, but do use envelopes in formal occasions instead.

这是一个电子邮件横行的年代，但正式的商务场合还是请用信封。

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Duke is also in formal occasions, wear a crimson velvet coat, hat on the set four mink.

在正规场合公爵也穿深红色的丝绒外套，帽子上镶四条貂皮。

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For formal occasions, she almost always stepped out in gowns by fashion insider-only names like Naeem Khan, Peter Sorenen, Doo.ri Chung, Rachel Roy and J.

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In 1985 he went freelance, working regularly for a handful of families who wanted help on special occasions such as formal dinners and shooting weekends.

ECONOMIST: Domestic labour