______ people have become masters of their country ____ science can really serve the people.

   A.It is only then ;that         B.It is that;when

   C.It is only when; that         D.It is when;when

______ people have become masters of their country ____ science can really serve the people.

_______ the people have become masters of their country _______ science can really serve the people.

A. It is only then; that ?

B. It was that; when?

C. It is only when; that

D. It was when; then?

30．       the people have become masters of their own country that science can really serve the people.

         A．Only then   B．It is only when   C．Only when D．It is only then

_______the people have become masters of their country _______ science can really serve the people.

A. It is only then; that                    B. It was that; when

C. It is only when; that                    D. It was when; then

_______the people have become masters of their country _______ science can really serve the people.

1. A.
   It is only then; that
2. B.
   It was that; when
3. C.
   It is only when; that
4. D.
   It was when; then