I carried my briefcase with me through the airport.
We were unable to squeeze an executive briefcase in.
The lawyer opened his briefcase.The thief ran away with my briefcase.
It is almost correct: it simply needs an article before the word phone, to make the sentence "Yours is the briefcase with the phone ringing inside." This sentence could be the answer to the question, "Which briefcase is mine?""The briefcase with the phone ringing inside is yours" is a more common construction, however.
If this is your briefcase, you're going to have to move it.
That is the lawyers briefcase.
un attaché-case
"Lost" is a past-tense verb.
Yes, and if anyone argues you're ending a sentence with a preposition, they're wrong. In this case, 'inside' functions as an adverb answering the question "where is the phone ringing?" The possessive pronoun 'yours' is correctly taking the place of the noun briefcase as the subject of the sentence. The object of the linking verb 'is' is the complete noun clause 'the briefcase with the phone ringing inside'.
The barrister did not have all the information, because he had left his briefcase in the office.
Fundraise, briefcase, visualise.
pack, pocket, attache, handbag, briefcase, purse
Monorail is a noun. It is a type of transportation, much like a bus or train. Insert it into a sentence as you would with the word "train", for example. "Kate, with steaming coffee in one hand and a stiff briefcase in the other, rushed to board the monorail before it left the station."