1、come across

偶然發現;偶然遇見

I came across a group of children playing.

我碰到一群正在玩耍的小孩。

We like to identify and celebrate women's success whenever we come across it.

每當女性取得成功，我們都會表示認同并予以頌揚。

使產生…印象;給人以…的印象

When sober he can come across as an extremely pleasant and charming young man.

沒喝醉的時候，他看上去似乎是個極為彬彬有禮、討人喜歡的小伙子。

He came across very, very well.

他給人的印象非常非常好。

2、volatile

易變的;動蕩不定的;反復無常的

There have been riots before and the situation is volatile.

以前曾發生過暴亂，現在局勢不太穩定。

The international oil markets have been highly volatile since the early 1970s.

從20世紀70年代初開始，國際石油市場就一直很不穩定。

（人）易變的，情緒無常性的

He accompanied the volatile actress to Hollywood the following year.

第二年他陪著這位情緒無常的女演員去了好萊塢。

He has a volatile temper.

他脾氣反復無常。

（液體等物質）易揮發的，易發散的

It's thought that the blast occurred when volatile chemicals exploded.

人們認為，易揮發的化學物質爆炸時產生了沖擊波。