a

I saw a black cat crossing the street this morning.

(Chinese) 今天早上我看到一只黑猫过马路。

She wants to buy a new laptop, but she hasn't decided on the brand yet.

(Chinese) 她想买一台新笔记本电脑，但还没决定买哪个牌子。

Sarah worked very hard and got an A on her history final exam.

(Chinese) 萨拉学习非常努力，在历史期末考试中得了一个A。

In the US grading system, an A typically represents a score of 90% or above.

(Chinese) 在美国的评分体系中，A通常代表90分或以上的成绩。

The word "apple" starts with the letter A.

(Chinese) 单词“apple”以字母A开头。

In the NATO phonetic alphabet, "Alpha" represents the letter A.

(Chinese) 在北约音标字母中，“Alpha”代表字母A。