正常人心率超过180次/分时,引起心输出量减少的原因是()
A. 等容收缩期缩短
B. 快速射血期缩短
C. 减慢射血期缩短
D. 等容舒张期缩短
E. 心室充盈期缩短
When you meet someone, you could say:
A. Pleased to meet you.
B. How are you?
C. It was nice meeting you.
以下数据结构中,( )是非线性数据结构。
A. 树
B. 字符串
C. 对
D. 栈
在下面的程序段中,对x的赋值语句的频度为( )。FOR i:=1 TO n DOFOR j:=1 TO n DOx:=x+1;
A. O(2n)
B. O(n)
C. O(n2)
D. O(log2n)