Choose A, B or C to fill in the blank

Thinking about how we might be (1)............... in 10,20 or even 500 years is enough to make the mind melt. Will we still even be (2)…… planes (perhaps we (3) ............... flying our cars from Seattle to Paris)? What if in 100 years we could (4)............... straight to our next holiday destination?

While we (5)..............., engineers and designers all over the world are testing out what could become the (6) ............... of the future. Witness the just-launched prototype of the 'Superbus', (7)………. by CNN as the love child of a DeLorean and a stretch limo. We get die feeling these (8)…….. are often designed to be fast, fuel-efficient and, well, out-of-this-world.

Granted, some of them may never (9)............... to our roads, skies or 'teleportation passageways', but it's fun envisioning what the (10) ............... may hold.

(1)....................

• A. 
  travel
• B. 
  travels
• C. 
  travelling
• D. 
  travelled