Tip-off (noun)

●A secret warning or piece of secret information.（線報，密告，秘密消息）

Examples:

1.Following a tip-off from a friend, we sold all our shares in the company.

2.The man was arrested at his home after a tip-off to police from a member of the public.

On the spot (idiom)

●In the place where something has just happened.（當場，現場）

Examples:

1.Police arrested the robber on the spot.

2.Whenever there's a bad accident or fire, you can be sure the station will have a reporter on the spot.

Prone to sth (idiom)

●Likely to do something or be affected by something, especially something bad.（易於，傾向於）

Examples:

1.The coastal region is prone to earthquakes.

2.My sister is prone to sneezing because of her allergies.

A sure thing (idiom)

●Something that is certain to happen.（毫無疑問的事，十拿九穩的事）

Examples:

1.The president's re-election is now far from a sure thing.

2.It's a sure thing that he'll refuse to cooperate.

Can't stomach/stand (the sight of) sb/sth (idiom)

●Unable to tolerate someone or something.（不能忍受，受不了，頂唔順）

Examples:

1.I can't stand the sight of cooked carrots.

2.Nobody can stomach Tom when he smokes a cigar.