Animal psychologists believe most dogs are about as smart as a two-year-old human. Dogs can understand more than 150 words, count up to five, and notice simple errors such as one plus one equals three.

　　动物心理学家相信其实所有狗大概都有两岁婴儿的智慧。狗可以理解多于150个词汇，数数到5以上，还能辨认简单的错误像是一加一等于三。