You know, ________ knowledge of ________computer is necessary to a secretary(秘书).
#9894
A
a; /
B
the; the
C
the; /
D
a; a
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The president is talking on ____ phone with astronauts in ____ space. 
#8196
A
不填;the
B
the; the
C
the; 不填
D
不填;不填
____ lies in North America.
#10367
A
The United State
B
The United States
C
United States
D
A United State