Choose the correct options

1. Stuart [checked|was checking|had checked|is checking] in their luggage while Lee was shopping in the airport.
2. Cory [was driving|had been driving|drove|has driven] for 8 hours and was exhausted.
3. These days many nomadic tribes [have been facing|have faced|face|are facing] extinction.
4. The tribesman [had visited|visited|had been visiting|were visiting] the city three years ago.
5. This city is slightly [bigger than|big|as big as|the biggest] where I live.
6. This tribe is by far [older|the oldest|old|oldest] in Brazil.