Question

If we don't work late , we won't meet the deadline ..using unless

Answer 1

Answer:

"We won't meet the deadline, unless we work late."

"Unless we work late, we won't meet the deadline."

Explanation:

"If/then" and "Unless/then" statements are logical statements.  If you are going from 'If/then' to 'unless', you simply negate the 'if' clause and change 'if' to 'unless'

For example:  

If not A, then not B

becomes:

Unless A, then not B

You can basically read 'unless' as "If not".  Remember, in English, double negatives cancel each other.  "Don't not run", is the same thing as just 'run'.