---What are you busy with ? --- We are c
题型:选择题
问题:
---What are you busy with ?
--- We are carrying out a research ____ the causes of cancer.
A.into
B.onto
C.to
D.in
---What are you busy with ?
--- We are carrying out a research ____ the causes of cancer.
A.into
B.onto
C.to
D.in