The first use of atomic weapons was in 1945, and their power________ increased enormously ever since.

1. A.
   is
2. B.
   was
3. C.
   has been
4. D.
   had been

The first use of atomic weapons was in 1945, and their power ____increased enormously ever since.

A. is   B. was  C. has been  D. had been.

The first use of atomic weapons was in 1945, and their power ________ increased enormously ever since.

A. is             B. was   C. has been        D. had been

The first use of atomic weapons was in 1945.And their power _______ increased enormously ever since.

A. is B. was?

C. has been D. had been?