The successful launch of Tiangong1 symbolizes a further step for China to join in the________of space stations previously mastered by Russia and the US.
A.invention | B.production |
C.operation | D.preparation |
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The successful launch of Tiangong1 symbolizes a further step for China to join in the________of space stations previously mastered by Russia and the US.
A.invention | B.production |
C.operation | D.preparation |