1. Exploring ________space is exciting, yet dangerous. There is ________need for both robots and humans for space exploration.
A. the; a B. a; a C. /; a D. /; the
2. Scientific research results can now be quickly ________ to factory production.
A£®used B£®applied
C£®tried D£®practiced
3. Computer has become a(n) ________ part of my life, without which I can hardly deal with my job.
A£®special B£®specific
C£®essential D£®especial
4. I ________ on a sofa because my grandparents have been here for the weekend.
A. slept B. was sleeping
C. have slept D. am sleeping