Barking dogs seldom bite.
吠犬不咬人（意指：对于高声发出恐吓，或惯于大声吼叫的人，勿须当真）。

Every dog has his day.
凡人皆有得意日（意指：大家都有走运的一天）。

Dog does not eat dog.
同类不相残；同室不操戈。

a cat-and-dog life
争争吵吵的日子

Dog does not eat dog.
同类不相残，同时不操戈

Dumb dogs are dangerous.
不叫的狗咬人

Give a dog a bad name and hang him.
谗言可畏，欲加之罪，何患无辞

go to the dogs
每况愈下

hang-dog look
愁眉苦脸

If the old dog barks, he give the counsel.
老狗叫，是忠告。

Love me, love my dog.
爱屋及乌

He is a lucky dog.
他是个幸运儿。

lead a dog's life
过穷困潦倒的日子

not have a dog's chance
毫无机会

top dog
当权派；头儿

treat sb. like a dog
不把某人当人看

a hunting dog
猎犬

a lazy dog
懒汉

a gay dog
一个快乐的人

a dirty dog
下流坯

dog-days n.[pl.]
三伏天, 大热天; 无所作为的时期, 无精打彩的日子

A good dog deserves a good bone.
[谚]好狗应该啃好骨头, 有功者受赏。

A living dog is better than a dead lion.
[谚]死狮不如活狗。

A staff [stick] is quickly [soon] found to beat a dog with.
[谚]欲加之罪, 何患无辞。

An old dog barks not in vain.
[谚]老狗不乱吠; 老狗 一吠, 就得小心。

An old dog will learn no new tricks. (=You cannot teach old dogs new tricks.)
[谚]老狗学不了新把戏; 老年人很难适应新事物。

as [like] a dog with two tails
非常开心[高兴]