walk the dog
take the dog for a walk
這裏用至於是a,還是the 就要取決於語境了。
如果指特定的狗，毫無疑問得用the表示特指，泛指時用walk a dog；
還可以說walk my dog，walk his dog 等；
Why should your father have to be walking the dog out on a cold night while you take your ease by the fire?
為何妳的父親竟必須在這樣的寒夜出去遛狗，而妳卻烤著火悠閑自在？
The queue is one of the few places where the English are allowed to talk to each other without having been formally introduced. The others are when taking the dog for a walk.
排隊時是英國人可以不經正式介紹就互相交談的幾種場合之壹，此外還有如遛狗的時候。
As you can imagine, I was nothing loath to miss the Sunday morning church parade and readily volunteered to walk the dogs instead.
妳可以想像得到，我很高興沒去參加星期天早晨做禮拜的行列，卻主動樂意地去遛狗。
My neighbour was a good Samaritan when I sprained my ankle. She did all my shopping and took the dog for a walk every day.
當我扭了腳脖子時，我的鄰居不厭其煩地幫助我。她幫我購買所有的物品並每天幫我去遛狗。