don't shine at tennis.
我不擅长打网球。
I am no good at it.
我对它不擅长。
My sister is no good at arithmetic.
我妹妹不擅长算术。
Lack of talent or ability.
不擅长，笨拙缺乏天资或能力
I've never learnt the trick of making friends easily.
我一向不擅长轻易交上朋友。
I wouldn't say I was proficient at computer programing.
我看我并不擅长计算机编程。
I'm not very good at hacking but I'll give it my best.
我不擅长安装但是我会尽力。
He's not very good at description.
他不大擅长描写叙述.
He is not a good hand of write.
他不是一个擅长书法的人。
Not in my line.
这不是我所擅长期的
2.我不擅长说英语,用英语怎么表达你好
我不擅长说英语
I am not good at speaking English.
或者：I don't do well in speaking English.
be not good at = don't do well in （不擅长。。。）
保证准确率~
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祝你学习进步，更上一层楼！
不明白请及时追问，满意敬请采纳，O（∩_∩）O谢谢~~
