他成绩很不好英文怎么说

如果某人的英语成绩很不好，可以使用以下表达方式来形容：

英语成绩不佳：The person has poor Engpsh grades/scores.
英语不好：The person is not good at Engpsh.
英语成绩很差：The person has very poor Engpsh grades/scores.

这些表达方式都可以用来描述某人英语成绩不好的情况。

例句：

他的英语成绩不佳，所以他很难通过英语考试。(His Engpsh grades are not good, so he finds it difficult to pass Engpsh exams.)
她英语不好，所以她常常在英语课上听不懂老师讲的内容。(She is not good at Engpsh, so she often doesn't understand what the teacher is saying in Engpsh class.)
他的英语成绩很差，所以他需要加强自己的英语学习。(His Engpsh grades are very poor, so he needs to improve his Engpsh skills.)