Barking dogs seldom bite.
吠犬不咬人。（意指：对于发出恐吓，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。（风水轮流转。）
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
Give a dog a bad name and hang him. 
人言可畏。
go to the dogs
每况愈下 ；堕落
hang-dog look
愁眉苦脸
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
过着猪狗不如生活
not have a dog's chance 
毫无机会
top dog
当权派；头儿
a lazy dog
懒汉
a dirty dog
下流坯
as/like a dog with two tails
高兴得跟什么似的
be (old) dog at
对…有经验；对…很内行
Beware of a silent dog and still water.
提防不吠的狗,小心静止的水。
come like a dog at a whistle
一呼即来
It is ill to waken sleeping dogs.
别惹事生非。/别惹麻烦。
Hungry dogs will eat dirty puddings.
急不暇择, 饥不择食。
dog it
拈轻怕重，逃避工作
put on the dog
装模作样；装出斯文、有钱或有文化的样子
a dog in the manger
占马槽的狗；占着茅坑不拉屎的人
help a lame dog over a stile
助人于危难之中；雪中送炭
He who has mind to beat his dog will easily find a stick.
欲加之罪，何患无辞。