by letter

基本解释

The cell selection from the initial cell pool is done by letter affinity.
从初始细胞池中对细胞的选择由字母关联性来完成。
At first she did phone her sister and me occasionally, but for the past year has wanted contact only by letter.
开始的时候，她确实时常的给她的妹妹与我打电话，但是这几年她要求我们只通过书信联系。
That model went as follows: a small number of columnists opined on politics, culture and events. The readers responded by letter or email: a tiny proportion of that response saw the light of day.
这种模式如此进行：几个专栏作家对政治、文化和时事发表意见，读者通过信件或电子邮件作出响应—只有极小一部分响应会得见天日。

The sign is formed by a line across the right foot of the letter "R."
Here's a copy of a letter to Pound by Yeats when they were both living in London.
这有一份叶芝写给庞德的信,他们当时都住在伦敦。
耶鲁公开课 - 现代诗歌课程节选
Ephesians was written by a different disciple of Paul, and he was using as his model for a Pauline letter the actual letters of Paul, or at least some of them that he possessed and knew of.
以弗所书则由保罗的另一信徒执笔，他伪造保罗的书信,模板是保罗的书信，或者他所持有的一些保罗的书信。
耶鲁公开课 - 新约课程节选

When encountering an unknown word in kindergarten, we were told to sound it out, understanding it letter by letter.
FORBES: American Political Economy Is No Different From English Language