Ответ:
1) present simple
We don't see a...
Do we see a...?
2) present continuous
my friends are not sunbathing now
are my friends sunbathing now
3) Past simple
I wasn't at...
was I at..?
4) Past simple
Mike didn't buy..
Did Mike buy...?
5) Past simple
Willy and Bill didn't watch...
Did Billy and Will watch..?
6) future simple
my friends will not come..
will my friends come..?