第六部分：完型填空(第51～65题，每题1分，共15分)
阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案，涂在答题卡相应的位置上。
51
A on
B in
C about
D to
52
A indicates
B indicating
C indicated
D indicate
53
A completed
B terminated
C launched
D finished
54
A maintaining
B maintained
C maintenance
D maintain
55
A such a
B as such
C such that
D such
56
A by
B on
C through
D in
57
A which
B whether
C in which
D that
58
A providing
B offering
C supplying
D asking
59
A because
B therefore
C because of
D thus
60
A satisfied
B pleased
C skeptical
D confused
61
A less
B more
C faster
D farther
62
A how
B which
C that
D whether
63
A increased
B to be increased
C to increase
D increase
64
A levied
B taken
C consumed
D removed
65
A opaque
B transparent
C obscure
D ambiguous