Scientists say it may be five or six years ______  it is possible to test this medicine on human patients.
#92459
A
before
B
after
C
since
D
when
推荐题目
Carl Linnaeus made great contributions to ________ plant species.
#93953
A
group
B
have grouped
C
grouping
D
been grouping
 ________him that she would fail as she was so able and worked so hard.
#91958
A
It never occurred to
B
That never occurred to
C
It never occurred with
D
That never occurred for
The boss________company I worked in two years ago has________in solving such kind of problem.
#92635
A
whose; many experiences
B
who; many experiences
C
whose; much experience
D
which; much experience
The driver drove __ hit a big tree and the car came to a stop. 
#94564
A
too carelessly to
B
carelessly enough to
C
so carelessly that he
D
so careless that he