dogs laugh,but they laugh with their tails.

请求高手翻译．不甚感激！
会叫的狗不咬人是．．．never bark，我记得我看过哪个句子啊．

dogs laugh,but they laugh with their tails. I could not help but laugh.句子中but是什么词性？什么用法？ I could not help but laugh.句子中but是什么词性？什么用法？（希望高人指点） I miss you ,but ,you donnot know ,laugh or cry ,I donnot know ,I need nothing ,but,I wish you ..... People laugh and people cry.Some always try.Some say hi and some bay,others may forget yu but never laugh用法 laugh loud 还是laugh loudly? On the way of life,do as you like ---cry or laugh,but don't forget to move on.中文是什么意思 people laugh and peoplecry smile and laugh