Which of the following are the guidelines for writing formulas and equations?

A.Centering equations on their own separate lines.

B.Defining the symbols that are used.

C.Numbering all equations in sequence if referred to later.

D.Using equations as grammatical units in sentences.

E.Giving titles in any equations used.

正确答案：Centering equations on their own separate lines.；Defining the symbols that are used.；Numbering all equations in sequence if referred to later.；Using equations as grammatical units in sentences.