The brains of teenagers, but not adults, showed greater activity in two regions associated with rewards when they were being observed by same-age peers than when alone.

青少年在被同龄的人观察时，大脑中两个与奖励相关的区域比独处时表现出更剧烈的活动，成年人则不然。

youdao

When I learned to ride a bike, I asked him not to leave me alone, but he said it was time.

当我学骑自行车时，我叫他不要留我一个人，但他说是时候放手了。

youdao

But I do write best when I have a lot of time alone.

但是我写的最好的时候是我有大量单独时间的时候。

youdao

When people say everyone dies alone, they don't mean to be saying you die, but not in the presence of others.

当人们说大家都孤独而死，他们不是说你死亡的时候，身边没有他人。

耶鲁公开课 - 死亡课程节选

It might be very important and insightful, but you're not saying anything especially interesting about death when you say everyone dies alone, if it's also true that everyone eats their lunch alone.

很重要，很有见地，但这样提出每个人都孤独而死时,并未对死亡本身提出什么有趣特别的见地，因为说每个人都孤独地吃中饭也是对的。

耶鲁公开课 - 死亡课程节选

Sierra had planned to go on the trip with a friend, but went alone when the friend couldn't make it.

WSJ: Official: Police detain man over missing woman

In each of these stories there was a certainty of knowing right from wrong when they were alone, but somehow their judgement became clouded when they were in the company of friends and they did not speak up to the wrong they knew they were doing.

FORBES: Character Is What You Do When EVERYONE Is Watching

But Bush is hardly alone when it comes to a president going back on his tax promise.

CNN: Read his lips: Does tax pledge put Obama on shaky ground?