写日记一般用过去时.
下面一篇供你参考一下.
Today is May Day. I am very happy.
I went to a park with my parents in the morning . We went there by bus. The bus was full of people. There were so many people in the park. Some children were playing by the lake.They were singing and dancing in the park. I joined them. I played happily. We all had a good time . We came back homevery late in the afternoon.