Context #1 -
Teacher: Ok class, please put down your pencils and give me your tests. Time is up!
Student: But I'm not finished yet!
Teacher: Sorry, I can't give you extra time to finish.
Context #2 -
John: I can't believe my time here in Japan is already up! I've been here for a whole year teaching English and now I have to go back to California.
Sally: Yeah this year has flown by! We're going to miss you.
John: I wish I could stay longer.
Meaning: the idiom "time is/was up" is used to describe the fact that the time someone had to do something has run out. When the time you had to do something is gone, we say your "time is up." This idiom was taken from the LSI textbook titled "Reading Transitions," which is used to teach Level 4 Reading/Vocabulary classes at LSI schools. For more information please visitwww.languagesystems.com