China has long been a leader in the fiel
题型:选择题
问题:
China has long been a leader in the field of genetic research ________ improving agriculture.
A.aim to
B.aiming on
C.aimed at
D.aims with
China has long been a leader in the field of genetic research ________ improving agriculture.
A.aim to
B.aiming on
C.aimed at
D.aims with