Question

fill in the blanks with sometimes, always, or never.
A square is always a rectangle.
A square is sometimes a rhombus.
A rhombus is sometimes a square.
A parallelogram is never a trapezoid.
A trapezoid is never a kite.
A rhombus is never a rectangle

Answer 1

how can a rhombus be sometimes a square, but never a rectangle?

a square is always a rhombus

a rhombus is sometimes a square
so, a rhombus is sometimes a rectangle, since a square is always a rectangle.

as for trapezoids, some places define them as a quadrilateral with at least one pair of equal sides. If that is your definition, then a parallelogram is just a special case of a trapezoid.

If you allow the two pairs of congruent sides of a kite to be the same length, then a rhombus is a kite, and could also be a trapezoid.

Check the way your text defines the various shapes.