She was out of practice at singing.

她对唱歌荒疏了。

《新英汉大辞典》

I'm not very good at singing.

我不很擅长唱歌。

《柯林斯英汉双解大词典》

I'm good at singing and I can play the guitar, too.

我擅长唱歌，我也会弹吉他。

youdao

The day what belongs to the dayat night, the party of young fellows,robust, friendly,Singing,with open mouths, their strong melodious songs.

VOA: special.2009.04.12

which is such a shame because she was very good at singing.

这真的很令人遗憾，因为她唱歌很好听。

追忆艾米 - SpeakingMax英语口语达人

Look at line 120. Milton writes that this choir had been singing at the moment of creation. Not bad.

看到120行，弥尔顿写到这个唱诗班是在一个,创作的时刻唱歌的，不是不好的时刻。

耶鲁公开课 - 弥尔顿课程节选

When his coaches were ready to move on, Fry was gifted at singing their praises.

WSJ: Iowa: The Harvard of Coaching

"We're basically at the very beginning in Sark of looking at singing up to any sort of agreement, " she said.

BBC: Sark politician calls for better protection of species

Then he abandons that routine and goes into his more usual mode of loud recitation, which makes no pretense at singing.

NEWYORKER: Plug and Play