．We can never expect _________ bluer sky unless we create _________ less polluted world.
#7748
A
a；a
B
a；the
C
the；a
D
the；the
推荐题目
As ______ child, Salk did not show any interest in ______ medicine or science in general．
#9387
A
不填; 不填
B
the; 不填
C
a; 不填
D
a; the
Dr.Peter Spence，________ headmaster of the school，told us，“________fifth of pupils here go on to study at Oxford and Cambridge.”
#7636
A
/；A
B
/；The
C
the；The
D
a；A
He is 40 and he feels his career as ________ basketball player is coming to ________ end.
#7757
A
/；the
B
/；an
C
a；an
D
a；/