Break out (phrasal verb)

●If something unpleasant such as a fire, fight, or war breaks out, it starts to happen.（爆發，發生，出現）

Examples:　　

1.Does everyone know what to do if a fire breaks out?

2.With some particularly bad timing, the scandal has broken out just days before a public holiday celebrating Buddha's birth.

Tip of the iceberg (idiom)

●Superficial evidence of a much larger problem.

（冰山一角）

Examples:　　

1.The problems that you see here now are just the tip of the iceberg. There are numerous disasters waiting to happen.　　

2.These small local protests are just the tip of the iceberg.

Tar sb with the same brush (idiom)

●To think that someone has the same faults or bad qualities as another person.

（一竹竿打翻一船人，認為…是一丘之貉）

Examples:　　

1.I am a football supporter and I have to often explain that I'm not one of the hooligan sort because we'll all get tarred with the same brush when there's trouble.　　

2.He may be lazy, but if you ask me his friends are all tarred with the same brush.

Out of the blue (idiom)

●Unexpectedly.（出乎意料，突如其來，晴天霹靂）

Examples:　　

1.She seemed so surprised by the news that it must have come out of the blue.　　

2.She told me, out of the blue, that she was going to live in New York.

Look down on/upon sb (phrasal verb)

●To regard oneself as superior to others and thus act in a haughty or snobbish manner.（看不起，蔑視）

Examples:　　

1.The well-dressed businessman looked down on the kid wearing a T-shirt in the elevator, not knowing that he was the new CEO.　　

2.I have no idea why some people look down upon those who speak with an accent—that means they know at least two languages!