一、详细释义：
n.
老鼠，耗子
例句：
if you do not feed the cat, you must feed the rat.
不养猫必养鼠。
例句：
you look like a little drowned rat!
看你就像只小溺水鼠！
鼠辈，卑鄙小人
例句：
you dirty rat !
你这个卑鄙的小人！
例句：
even if you win , you're still a rat.
就算你赢了，你也只不过是个小人。
v.
捕鼠 [i]
例句：
the little boy likes to rat.
这个小男孩喜欢捕鼠。
例句：
have you ever heard about dogs going ratting?
你听说过狗拿耗子吗？
弄蓬松 [t]
例句：
she ratted her hair whenever she went to big parties in the evening.
她每次晚上出去参加大型晚会时都用发垫把头发垫得高高隆起。
告密，出卖 [i]
例句：
to our surprise they have ratted on us.
令我们吃惊的是他们居然把我们出卖了。
例句：
they were accused of encouraging children to rat on their parents.
他们被指控唆使儿童告发自己的父母。
违约，食言 [i]
例句：
she claims he ratted on their divorce settlement.
她声称他违反了他们的离婚协议。
例句：
we should not rat on our promises.
我们不应违背诺言。
二、词义辨析：
mouse,rat
这两个名词均可表示“老鼠，耗子”之意。 mouse一般指体形较小的家鼠。 rat一般指生活在室外体形较大的一种老鼠。
三、相关短语：
rat race
n.卑鄙的竞争,你死我活的竞争 [电] 环形波导
rat snake
n. 吃鼠的蛇
cotton rat
棉鼠
pocket rat
囊鼠类
rat kangaroo
鼠袋鼠
rat typhus
地方性斑疹伤寒
rat-tail file
鼠尾锉
sewer rat
n. 褐家鼠
water rat
n. [动]河鼠
black rat
【医】 黑鼠
brown rat
【医】 棕鼠, 褐鼠, 沟鼠
wood rat
【医】 森林鼠
四、参考例句：
you dirty rat !
你这个卑鄙的小人！
a rat is an animal.
老鼠是一种动物。
you look like a little drowned rat!
看你就像只小溺水鼠！
we should not rat on our promises.
我们不应违背诺言。
i smelled a rat in the matter.
我感到这件事有问题。
yes, only a rat puppet beat them out.
没错，只有一个老鼠木偶打败过他们。
a rat had gnawed a hole in the box.
老鼠在箱子上咬了一个洞。
the cat caught a big rat in the kitchen.
猫在厨房捉到了一只大老鼠。
the hungry rat ravened down the poison bait.
饥饿的老鼠一口吞下毒饵。
it is really a great shame to rat out.
临阵脱逃真可耻。