给定一个文本，将其中语法上的错误报告出来。输入应该是一段英文文本。输出应该是文中包含的语法错误。


"As a engineer, he was expected to have good knowledge of their domain. But, he didn't seems to possess such knowledge. "
语法错误: 

- "As a engineer" -> 应该为 "As an engineer" 因为 "engineer" 的发音以元音音素开头。
- "didn't seems" -> 应该为 "didn't seem" 因为主语是 "he"，所以动词应该用单数形式。