If I don't send a picture, he will smell a rat.

如果我不寄张照片，他会起疑心。

《柯林斯英汉双解大词典》

I smell a rat.

我觉得事情不妙。

youdao

The repeat patterns in the smoke made lots of people smell a rat and it turned out that Hajj had even copied some of the buildings.

烟雾中重复的样式让很多人感到可疑，结果证实，哈吉甚至复制了其中的一些建筑物。

youdao

Money manager Ken Fisher's latest book is How to Smell a Rat: The Five Signs of Financial Fraud (John Wiley, 2009).

FORBES: Good News

Now, by naming politicians, Mr Singh may have ensured that he keeps his job (the High Court will smell a rat if he is sacked).

ECONOMIST: India

Fisher has written seven books, including How To Smell A Rat, The Ten Roads To Riches, The Only Three Questions That Count, Super Stocks, The Wall Street Waltz and 100 Minds That Made The Market.

FORBES: Next Week's Guest: Ken Fisher