6 (prettiest)
7(happier)
8(more careful than Ivan)
9(most laziest),(in the class)
10(more beautiful than)
1) have walked;
2) have been walking;
3) have been eating;
4) has slept;
5) have worked;
6) have been working, has said;
7) Have you heard;
8) have you picked, have been picking;
9) Have you seen, have been looking
<span>They are near a/<span>the waterfall.</span></span>