The 'b' had been wrongly written as a 'd'.

b错写成d了。

《牛津词典》

In the A, B, C, D and F grading system, the first four letters are typically considered passing grades.

在 A、B、C、D 和 F 评分体系中，前四个字母通常被认为是及格。

youdao

After you hear a question, you must choose the best answer from the four choices marked A, B, C and D.

听到问题后，必须从A、B、C、D四个选项中选出最佳选项。

youdao

An A is worth four points, a B three points, a C two points and a D one point.

VOA: special.2009.03.05

I quote in here a guy who croaks before this course starts, Jean Bodin, B-O-D-I-N.

在这儿我引用一位逝者提出的观点,金博丹

耶鲁公开课 - 欧洲文明课程节选

Again I should have said first, index 0, the first one. I can similarly go in and say I'd like all the things between index 2 and index 4. And again, remember what a b c that does. Index 2 says start a 0. 1, 2. So a, b, c.

我还是要说一遍，索引为0的元素，是第一个元素，我可以要求返回索引,2和4之前的所有元素，请记住2,是从0开始的,那么0，1，2对应的是。

麻省理工公开课 - 计算机科学及编程导论课程节选

It's 25 kilometers round in a town called Badme, B-A-D-M-E.

NPR: Africa Update: Somalia, Eritrea and Sudan

If any four atoms, let say, atoms A, B, C and D, would be selected to test the decay, atom A would have much lesser chance to respond to decay due to the existence of atoms B, C and D.

FORBES: Young Earth Creationists Whipsawed By IRS

Patrons can order a shot of vitamins A, B, C, D and E or a mixture of roots, herbs, fruits and mushrooms blended in blasts called "energy, " "immunity" and "skin, hair and nails" to add to their water.

WSJ: Something in the Water? Tapping an Idea in New York City