A.史努比有一个成功的主人
B.史努比是一只恋爱中的幸运狗
C.史努比是一个成功的作家
D.史努比可以给我们上人生课
根据第四段By 1957 he could walk on two legs and was going to school with his master, Charlie Brown, who failed at just about everything.（到1957年，他可以用两条腿走路，并和他的主人查理·布朗一起上学，而他的主人几乎什么都失败。）可知，史努比的主人并不成功，A项错误。
根据最后一段第一句Snoopy easily falls in love but always has his heart broken.（史努比很容易坠入爱河，但他总是心碎。）可知，B项错误。
根据倒数第二段However, Snoopy has always dreamed of being a famous writer. The beginning of. his story is always,"It was a dark and stormy night..." Unluckily for him no one has ever wanted to publish the story.（然而，史努比一直梦想着成为一名著名的作家。的开始。他的故事总是:“那是一个漆黑的暴风雨之夜……”不幸的是，从来没有人愿意发表他的故事。）可知，C项错误。
根据最后一段第2-3行 If you think a little about his words, you might find them full of life lessons. （如果你仔细想想他的话，你会发现里面充满了人生的教训。）可知，可以从史努比那学习到人生的教训。故选D。
