翻译如下：

我吃了一个汉堡包。

I ate/have eaten a hamburger.

我有一个汉堡包。

I have a hamburger.

我还没吃午饭。

I haven't had lunch yet.

我已经吃过晚饭了。

I have already had supper.

我刚才吃过晚饭了。

I had supper just now.

今天中午我吃了两碗米饭。

I ate/had two bowls of rice for lunch today.