My favourite animal is dolphins.
My favourite animals are dolphins
这两种都是可以的,只要语法正确就没有问题的.
还可以回答：
I like dolphins best.
我最喜欢海豚啦!My favourite animal is dolphins.复数前面为什么可以用is呢？My favourite animal is dolphin. My favourite animals are dolphins. I like dolphin best.I like dolphins best.什么意思？My favourite animal is dolphin. My favourite animals are dolphins. I like dolphin best.I like dolphins best. 这四句是正确的。 My favourite animal is dolphins. 这句是不对的。