There’s no way of knowing why one man makes an important discovery         another man, also intelligent, fails.
#39533
A
since
B
If
C
as
D
while
推荐题目
 Fish sleep _____ their eyes ______.
#38776
A
with;open
B
without;open
C
with;close
D
with;closed
Nobody is as ______ as Sandy, so we all like to be friends with her. 
#37357
A
politely
B
carefully
C
likely
D
friendly