【多选题】在检索文献时,使用逻辑“与”是为了( )。
【单选题】关于HIV的致病机制,错误的是( )
A.
HIV主要侵犯CD4+T细胞,并在其中增殖破坏细胞
B.
HIV主要侵犯CD8+T细胞,导致细胞免疫功能下降
C.
HIV亦可侵犯单核巨噬细胞、DC、小神经胶质细胞等
D.
感染HIV后,CD4/CD8比例降低甚至倒置
E.
HIV的gpl20与细胞膜MHC-Ⅱ类分子有共同抗原,导致自身免疫损伤
【单选题】What does Professor Carole Counihan say about. pre-industrial European families eating meals together?
A.
It was helpful to maintaining a nation's tradition.
B.
It brought family members closers to each other.
C.
It was characteristic of the agrarian culture.
D.
It enabled families to save a lot of money.
【单选题】听力原文:M: The chicken dish is really spicy. W: So is the salad. Q: What does the woman mean? (17)
A.
Rice Should be served with the chicken.
B.
The dishes here are never spicy.
C.
There really is chicken in the salad.
D.
Both the chicken dish and the salad taste spicy.
【单选题】Constance Hale says 'email has been an incredible boon to communication'.What Does she mean by this?
A.
People want to see the person they are talking to on the phone.
B.
email is easier than talking on the phone.
C.
People are using writing and reading more with email.
D.
email is not private enough.