an
英 [ən] 美 [ən]
det.
(指初次提及或非特指的人或物)一(个);(一类人或事物中非特指的)任何一(个);(用于前加形容词或后加修饰语的不可数名词之前)一(种)
an associate degree in nursing.
Listening is an important part of the job.
倾听是这项工作的一个重要部分。
It takes at least an hour to get home from work.
下班回家至少得花一个小时。
《牛津高阶英汉双解词典》
An accurate diagnosis was made after a series of tests.
准确的诊断是在一系列的检查后作出的。
《牛津高阶英汉双解词典》
I think you have made an error in calculating the total.
我想你在计算总数时出了差错。