Verb conjugation of "whistle" in English

It looks like we need to invite Erika again to my home, once the cake is ready. Of course, this should be done before Sunday to stay in the chocolate cake race. We should buy cream too.
This afternoon I will fly to Chile. My two brothers and sisters live there. They are also very old and my brother has already died. My parents emigrated 30 years ago, but they wanted to stay.
I can already speak a little English but not too well. So I'm more cautious about making mistakes. I want to improve my English, because it is also good for your confidence and communication skills.