单词分类；请根据所给句子的意思，从下面的方框中选出可以填入句子中的单词，并将其字母标号填在答题卷相应的位置。

Do you know that scientists have           /           water on Mars?
We all like the music because it is very         /        .
He is a clever boy and he can play the         /          very well.
Tony’s father is a famous          /         .
You should smile when you like           or          .