Apart from [Except for] a few grammatical mistakes, this composition of yours is well written.

除了几处语法错误之外，你这篇作文写得不错。

《新英汉大辞典》

Check for spelling and grammatical mistakes.

检查拼写和语法错误。

youdao

There were few grammatical mistakes in his composition.

他的作文几乎没有语法错误。

youdao

Children make grammatical mistakes all the time but then they go away and they go away without correction.

儿童们总是会犯些语法错误,但随后这些错误无需纠正也都消失了

耶鲁公开课 - 心理学导论课程节选

and you've received assignments that are just riddled with grammatical mistakes,

而你又收到了满是语法错误的作业，

对于抄袭的想法 - SpeakingMax英语口语达人

Not succumbing to malapropisms and grammatical mistakes does not make you a good public speaker.

FORBES: Magazine Article

Beware of common grammatical mistakes, like subject-verb agreement.

FORBES: Magazine Article