9. I can't sing for nuts!
我一点也不会唱歌！
还能这样说：
I have no ear for music.
I'm tone-deaf.
应用解析：
not care a (rotten) nut 毫不在乎；
a hard nut to crack 棘手；难对付；
off one's nut 疯狂的，失去理智的
10. When he sings to his wife, he has fire in his eyes.
他给妻子唱歌的时候眼睛里很有神采。
还能这样说：
He gets stars in his eyes when he sings to his wife.
He is full of passions when he sings to his wife.
谚语：
Where there is smoke, there is fire.
无风不起浪。
11. It is a waste of money to sing in KTV when you are not happy.
当心情不好的时候去KTV唱歌是一件浪费钱的事情。
还能这样说：
You are squandering your money to sing in KTV when you are not in a good mood.
If you are unhappy, you had better not go to KTV, or you will waste your money.
谚语：
Money talks.
有钱就灵。
12. He was touched by these sweet songs.
这些甜美的歌曲触动了他的心扉。
还能这样说：
These sweet songs affected him.
He was moved by these sweet songs.
应用解析：
sweet on 爱上，钟情于……
sweet nothings 情话；
short and sweet 简短而愉快的；
keep sb. sweet 讨好某人；
sweet with 有……的甜（香）味；
be sweet on sb. 喜欢或爱上某人