休克指数
参考答案:休克指数:是指脉搏与收缩血压的比值。
已知一种碳原子的质量为1.99×10-26kg,氧的相对原子质量是16,则一个氧原子的质量是多少?
—Do you know that Jack () a postman for about six years
—Yes, I see.
A. has become
B. has turned
C. has changed
D. has been