從A、B、C、D四個(gè)選項(xiàng)中,選出可以填入空白處的最佳選項(xiàng)。
21.Today CCTV offers a _______of programmes to satisfy different needs and _______.
A.many; interests B.number; habits C.variety; tastes D.deal; likes
22.If we know more about _______causes the problem, we may take measures before it is _______late.
A.what; too B.which; very C.that; already D.that; so