Choose the correct option

1. This car is too small for our family. We need
   [much bigger|more bigger|the biggest]one.
2. The exhibition in the new art gallery was great! It was
   [more very interesting than|further more interesting than|far more interesting than]
   I thought.
3. I'm surprised that she's
   [slightly more older|more slightly|slightly older]than me. She looks younger.
4. The problem with the finance was
   [much more complicated than|much complicater than|more complicated then]
   we expected.
5. You must drive
   [a bit slower|a bit more slowly|a bit slowlier]. There's a speed limit sign here.
6. The situation with his grandfather's health is
   [much more serious then|much more serious than|more seriously than]
   he thought.
7. It's
   [a bit cooler|a bit cooller|more cooler] today than it was yesterday.