1. a case of mistaken identity They talked to me as though I were my twin sister. It was clearly a case of mistaken identity.
2. a change of habit
Unless you show a change of habit, you will fail.
a chief executive officer (CEO)
The CEO is the Chief Executive Officer, the head of the company.
4. a combined total
They added the subtotals of the two sections to arrive at the combined total.
5. a crucial component
Studying is a crucial component in academic success. A student cannot succeed without studying.
6. a day off /a week off /a month off / time off
She wanted a week off, but her boss only gave her three days off.
7. a dirty trick/dirty tricks
He played a dirty trick and deceived them.
a fat cat
Some say that rich, privileged people are fat cats.
8. a flat out lie /a flat out guess
She meant to deceive them, but they caught her, accusing her of a flat-out lie.
He didn't win the count-the-pennies contest through skill, he just made a flat-outguess.
9. a habitual liar
Why believe her? She's just a habitual liar. She lies as a habit, a lot of the time, about many things.
Homework: write a simple definition of the vocabulary we learned today.