一半蛋糕怎么说英语

In Engpsh, you can say "half a cake" or "half of a cake" to refer to half of a cake. For example, you could say:

"Can I have half a cake for dessert?"

"I only want to eat half of the cake, so can you cut it in half for me?"

"I'm trying to watch my portion sizes, so I only want to eat half of a cake."

I hope this helps! Let me know if you have any other questions.