听到好消息,大家不约而同地鼓起掌来。Tīngdào hǎo xiāoxi, dàjiā bùyuē'értóng de gǔ qǐ zhǎng lái.Hearing the good news, everyone started clapping at the same moment.
看到老师进来,同学们不约而同地站了起来。Kàndào lǎoshī jìnlái, tóngxuémen bùyuē'értóng de zhàn le qǐlái.When the teacher came in, the students all stood up at once without any signal.
我们不约而同地选了同一件礼物。Wǒmen bùyuē'értóng de xuǎn le tóng yí jiàn lǐwù.We happened to choose the very same gift.