6) we wasn't / weren't in the desert last year. что поставить? wasn't или weren't.

Weren't потому что множественное число)

Weren't поставь удачи

1 January - the Euro introduced in non-cash transactions
January 12 - Ousted Malian dictator Moussa traoré and his wife were sentenced to death for major theft
January 24th - Columbia. A strong earthquake, over 700 dead, over 3,000 wounded
January 25 - about a thousand people died because of the earthquake in Colombia.
January 28 - Moscow hosted the final of the first international beauty contest "Miss Commonwealth"
January 31 - the first part of the cult game series Silent Hill (the first video game in the genre of survival horror)
16 February in Tashkent (Uzbekistan) there was a terrorist attack — a series of explosions
February 16 - in Belarus began the census
On 20 February in Moscow in the Kremlin Palace the premiere of film Nikita Mikhalkov

1. Is there a book on the table? Where is the book? What is there ion the table? There is a book on the table, isn't there?
2 Must he work hard today? He must work hard today, mustn't he? Who must work hard today? When must he work hard? What must he do?
 3. are we leaving for Moscow next week? We are leaving for Moscow next week, aren't we? Who is leaving for Moscow next week? Where are we leaving for? When are we leaving for Moscow?
4. Were we  reading the whole evening? We were reading the whole evening, weren't we? What were we doing the whole evening? When were we reading.
5. Don't they  go to work on Sunday? They don't go to work on Sunday, do they? What don't they do on Sunday? Where don't they go on Sunday? When don't they go to work?
6.  Is it not cold today?  It is not cold today, is it? When is it not cold?