希腊字母phi（希腊字母表中的第21个字母）经常用于数学中。

The Greek letter phi is often used in mathematics.

在几何学中，phi（希腊字母表中的第21个字母）代表黄金比例。

In geometry, phi represents the golden ratio.

许多古希腊文本中包含字母phi（希腊字母表中的第21个字母）。

Many ancient Greek texts include the letter phi.

俄罗斯正在举办第21届世界杯。

Russia is holding the twenty-first FIFA WORLD CUP now.

在第21行，另一种说奖励的方式是关于期望。

In line 21, another way to say as a bonus would be about expectation.

在第21行，作为奖金的另一种说法是高于预期。

In line 21, another way to say as a bonus would be above expectation.

第21段第四部分 “红色十月”

Segment 21d. Red October.

阿莱克斯飓风公开报道第21号.

Hurricane Alex Public Advisory No. 21.

他在第21节中引证了第六条戒律。

He has just quoted the sixth commandment in verse 21, and He says, “But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment.

这份报告是该组织的第21次调查。

This report is the group's 21st survey.