61%of ulcer risk seems to be caused by
A. unknown factors.
B. economic factors.
C. environmental factors.
D. genetic factors.
查看答案
Hermann Toplak suggested than more money should be spent on
A. surgery.
B. fat people.
C. preventive programs.
D. state health services.
When a stroke occurs,the arteries leading to and within the brain._______
Up to now,the work has been easy.
The experiment proved to be satisfactory.