成人心肺复苏时血管加压素的用法为
A.一次性静脉推注40U
B.40U,每5分钟重复一次
C.一次性静脉推注20U
D.20U,每5分钟重复一次
参考答案:A
I _____ worry about my weekend-I always have my plans ready before it comes. [ ]
A. can't
B. mustn't
C. daren't
D. needn't
若一棵二叉中只有叶结点和左、右子树皆非空的结点,设叶结点的个数为k,则左、右子树皆非空的结点个数是 【1】 。