EXI work eight hours every day -> I work an eight-hour day
1.I'm going on vacation for three weeks
-> I have a.
2.There was a delay of 10 minutes
-> There was a.
3.This word has 4 letters
-> This is.
4.These boys are 15 years old
-> These are.
5.We will study this lesson in 3 periods
-> We will study
a.