2. 类似

biological parents 亲生父母 

parent children 亲生子女 

arm wrestling 拗手劲 

black sheep坏事之徙 

You cur!你这狗！

dish cloth抹碗布 

emergency room 急诊室 

as slippery as an eel 滑如泥鳅

3. 不同比喻

Be diplomatic 讲究策略

as dull as a goose 呆若木鸡

as timid as a rabbit 胆小如鼠

as warm as a toast 溫暖如春

as clean as a whistle 于净如雪

as long as the hills 天长地久

as American as apple pie 地道的美国味

eager beaver摩拳擦掌；积极想动手干的人

as straight as a pumpkin vine 直得像沙钩

a visit by the stork喜得贵子

The couple are leading a cat-and-dog life. (They quarrel often.) 

4. 风格对等，含义对等但表达不同

软禁 house arrest 

手续费 service charge 

甜蜜的回忆fragrant memories 

音响系统 speaker (sound) system