Put a space between scientific research and time unit. Before and after the function (Roman font), unless there are brackets, add spaces. When a mathematical operator is used as a verb or conjunction, that is to say, there are numbers on both sides of the operator, or when one side is a variable symbol and the other side is a number, spaces should be added before and after it. Except%, $,angle unit o,', ",when using other measurement or time unit, there must be a space between the number and the unit. Generally speaking, English papers need to add spaces after punctuation marks.

Usage of special punctuation marks

1) Ellipsis: In English, … is used as ellipsis, and there is no need for spaces before and after ellipsis (note: ellipsis is of little use in scientific papers).

2) Brackets and quotation marks: spaces should be added before and after quotation marks and parentheses, and spaces are not needed in quotation marks and parentheses.