自2010年至今的四级考试中， 共出现过 次
自2010年至今的六级考试中， 共出现过 次
N-COUNT 老鼠;耗子 A rat is an animal which has a long tail and looks like a large mouse.
This was demonstrated in a laboratory experiment with rats.
...a rat-infested derelict building.
N-COUNT 卑劣的人；不忠实的人；小人 If you call someone a rat, you mean that you are angry with them or dislike them, often because they have cheated you or betrayed you.
What did you do with the gun you took from that little rat Turner?
VERB 告密;出卖 If someone rats on you, they tell someone in authority about things that you have done, especially bad things.
They were accused of encouraging children to rat on their parents.
VERB 违约；食言 If someone rats on an agreement, they do not do what they said they would do.
She claims he ratted on their divorce settlement.
PHRASE 怀疑有问题；发现不对头；有所警觉 If you smell a rat, you begin to suspect or realize that something is wrong in a particular situation, for example that someone is trying to deceive you or harm you.
If I don't send a picture, he will smell a rat...
Though Lloyd George's behaviour seemed curious, Haig still did not smell a rat.