They are travelling around Australia.

They aren't travelling around Australia.

Lucy leaves on Tuesday.

Lucy didn't leave on Tuesday.

Chris wasn't watching a programme about snakes.

Chris weren't watching a programme about snakes.

I haven't seen photos of the Australian Outback. 

I hasn't seen photos of the Australian Outback. 

You'd need to drink a lot of water.

You won't need to drink a lot of water.

We aren't going to fly to Sydney.

We will not fly to Sydney.

sometimes

next week

next week

at the moment

tomorrow

last weekend

never

sometimes

next week

last week