Why must we most often put "does" in the present tense?
*****
NOT A TEACHER *****
Hello, George:
The teachers have already given you the answer.
I just thought that you would appreciate this extra information.
I am sure that you have heard of a famous English writer named Shakespeare (1564 - 1616).
A brilliant scholar tells us that in Shakespeare's day, English speakers sometimes used "does" and sometimes didn't use "does." Shakespeare wrote "Thus conscience
does make cowards of us all." Today in modern English, it would be "Thus conscience make
s cowards of us all."
There was no "rule."
The scholar says that some people in those days might have used "does" for "dignity [it sounded elegant], euphony [a pleasant sound], rhythm, emphasis [which we do today], often from mere caprice [because the writer just wanted to]." Don't be surprised if you see this use of "does" in poetry or legal language nowadays.
*****
You come here for
modern English, so be sure to follow the teachers' advice.
That scholar is George Oliver Curme in his 1931 masterpiece
A Grammar of the English Language, Vol. II, page 23.