______ life began on earth is one of the biggest puzzles that scientist found hard ______.
A. How; solving B. When; to be solved
C. How; to solve D. Which; to solve
Was it because his mother was ill ______ he didn’t go to school?
A. so B. that C. why D. when
Our teacher asked us to give all the used books to ______ needed them.
A. all B. whom C. those D. those who
We have got plenty of time. We ______ hurry.
A. needn’t B. mustn’t C. shouldn’t D. cannot
She was afraid that unless the train speeded up she would miss her ______ to Scotland.
A. ticket B. place C. seat D. connection
Just as some experts say, shopping by television will never take the place of shopping in ______ stores, because many people find shopping at a store ______ great enjoyment.
A. a; the B. the; a C. a; / D. /; a
