Verb conjugation of "zielen" in German

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.
You have to be careful when you go on summer vacation. There are many dangers but the most dangerous one is the sun itself, because if you're not careful it may harm you. People underestimate the rays.
I'm also not interested in such things, but I had a classmate who recommended the book 'Mice and Men' and that's why I bought it. It is a very interesting book and tells about old times in the U.S.