The first letter of the first word in a sentence should be a capital letter

Which is correct?

My grandparents walk _____ twenty minutes a day.

We have been dating _____ a long time.

My family has lived here _____ last March.

There ______ a red car parked in our driveway.

There ______ six eggs in the fridge.

I _____ to the mall after school.

_____ you see Jody's new dog yesterday?

Which is correct? "Do you think Maria is _______ than Selena?"

Which is comparative? "Whose English is _______? Mine or his?"

What are these?

The ocean is salty.

Does the sun come out at night?

Cars can swim.

People breathe underwater.

The capital of France is London.

The capital of France is Paris.

The capital of England is London.

The capital of China is Beijing.