While other scientists are keeping____eye on changes in the H5N1 bird flu strain, the scientists in England are working on vaccines, in case it becomes highly infectious in ____humans.
#9824
A
a , /
B
an, /
C
the, an
D
an, the
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Aborigines' most common tool in Australia is ________ boomerang, which is used to kill ________ animals.
#10144
A
the;/
B
/;/
C
the; the
D
/;the
What ____ great fun we are having! I’ll never forget ____ Christmas like it.
#7600
A
a; a
B
a; the
C
a; /
D
/; a
Tom, Jack and Rose were named as assistant professors. Believe it or not, ______ three of them were of ______ age.
#9927
A
不填; an
B
不填; the
C
the; an
D
the; the
When the spaceship traveled above, __________ new-looking earth appeared before us, ______ earth that we had never seen before.
#10038
A
a; an
B
the; an
C
/; the
D
a; the
He was elected______ president of the company, and _____news came ,in fact, as ______surprise.
#9399
A
a; the ;X
B
X; the ; a
C
a; X; the
D
the; the; a