You … leave by 6 0'clock or you'll be late. 1) mustn't 2) must

You must leave by 6 o'clock or you'll be late

Надо записать must

You must leave 6 o`clock or you`ll be late.

Можно мой лучший

If I’d known they were looking for people to live on the space station, l would have applied for the job! Conditional III
Если бы я знал,что они ищут людей для жизни на космической станции,я бы непременно устроился на такую работу( все осталось в не знал/не устроился )
Возможен вариант с Mixed Type
If I’d known they were looking for people to live on the space station, l would apply for the job!
Если бы я знал,что они ищут людей для жизни на космической станции ,я бы сейчас устроился на такую работу.

1. Shall we have dinner in a cafe?
We will not have a dinner in a cafe.
2. Did your agent supply the provision?
Your agent didn’t supply the provision.
3. Were there passengers on board of our ship?
There were not passengers on board of our ship.
4. Was he busy at that time?
He wasn’t busy at that time.
5. Is the second mate on match now?
The second mate isn’t on Match now.
6. Are we picking up the speed?
We aren’t picking up the speed.
7. Had the seamen repaired the engine by themselves?
The seamen hadn’t repaired the engine by themselves.
8. (Не уверена) Shall we have built 12 ships of this series by next October?
We will not have built 12 ships of this series by next October.