缩手反射活动的完成说明多细胞生物完成复杂生命活动依赖于:[ ]
A.单个细胞活动
B.人体各器官和系统配合
C.神经细胞独立活动
D.各种分化的细胞密切配合
答案:D
要达到胸外按压效果,应该()。
A.正确的按压位置
B.正确的按压姿势
C.按压的操作频率
D.按压的力量大小
根据句意,用括号内所给单词的适当形式填空。
1. They don't allow ____ (smoke) in public. It's impolite.
2. I really don't know if he wants to make a correct ____ (choose).
3. The book is ____ (suit) for students to read.
4. —What does his father do? —He is a ____ (manage).
5. The show is very ____ (attract), so many people want to watch it.