One day， _____，Newton saw an apple fall from a tree.

1. A.
   to sum up
2. B.
   what’s more
3. C.
   it is said
4. D.
   in addition

One day， _____，Newton saw an apple fall from a tree.

A.to sum up         B.what’s more          C. it is said     D.in addition

One day， _____，Newton saw an apple fall from a tree.