Many of us like to think our dogs are smart, as we point to their ability    1    (read) our facial expressions and understand    2    we say. But some dogs are    3    (except). Chaser,    4    American border collie could recognize and remember 1,022 nouns — one for each of her    5    (toy).

The scientists recruited dog owners and asked them to play fetch with their dogs    6    (day) in their homes while    7    (repeat) the name of the toy, a process    8     lasted three months. Dogs that succeeded    9    (give) a new toy and new name to learn. Despite the intensive training, only one dog, Oliva, learned to match a single word to a toy. In fact, she learned 21 names in two months. It’s    10    (interest) that except Oliva, none of the breeds learned a thing. It was such a surprise.