1.   Her voice suddenly sounded deadly serious.

2.   His voice sounded serious.

3.   But now Tomba sounds almost serious when he talks about marriage.

4.   He almost sounded serious.

5.   He sounds deadly serious.

6.   Her voice sounded serious and my heart sank.

7.   Landis, sounding serious, said the man in the gorilla suit had gone on to win five Academy Awards.

8.   She sounds so serious, so driven.

9.   Sounds serious.

10.   Sounds serious?