[ACQ/CV-05001] Understanding Relation Between Existence of Derivative and Being Analytic

The statements below refer to functions of complex variable.
Complete the sentences given below. Use one of phrases
      must be;  need not be;   is always;  is never; does not;
You may  select your own words, if you wish.

1. A function, which is analytic every where,  ________________ differentiable every where.
2. A function, which is differentiable every where,  ____________________analytic every where.
3. A function, which is differentiable at a point, _____________________ analytic at that point.
4. For a function which is analytic at a point, its derivative _________________ exist at that point.
5. A function  __________________ be analytic at an isolated point.
6. A function __________________ be differentiable at an isolated point.