【简答题】 is said ______ the biggest health challenge to both men and women in that area over the past few years. A. that it is B. to be C. that it has been D. to have been
【单选题】AIDS Acquired Immunodeficiency Syndrome (AIDS), is a kind of human viral disease (病毒病) that damages the immune system, weakening the body's ability to defend itself from infection and disease. Caused ...