The band must reach the concert in time to do their performance.
Sometimes people must fend for themselves.
Yes you can use the word Mohammed ... But u must not make fun of it .
He must make the putt, otherwise, he will go into the playoff.
Using the word "then" at the beginning of a sentence is not incorrect. However, it does not make a sentence complete. A complete sentence must have, at a minimum, a subject and a verb. "Then" is neither of those.
Someone with real artistic talent must have painted this mural.
I must prove he has slandered me with his gross innuendo or the judge will not award me damages.
We must twist our way through the abandoned vehicles; quickly now...
Here is a sentence with the word answer; A student must answer all the answers on a test.
Yes I certainly can make a sentence with that word.
No. This is a sentence with only one word: "Go."
To make road stone you must first pulverise larger rock fragments.
It was so cheap that I thought that it must be a fake, but it turnegoyd out to be completely authentic.