Stroll: a slow relaxed walk 散步,溜达,闲逛
We went for a stroll in the park.
我们去公园散了散步.
Spot: to see or notice a person or thing, especially suddenly or when it is not easy to do so 看见,看出,注意到,发现
I finally spotted my friend in the crowd.
我终于在人群中看见了我的朋友.
I've just spotted a mistake on the front cover.
我刚才在封面上发现了一处错误.