在超声造影时背向散射回声强度测定,可用于()。
A.定量评价超声造影图像
B.加快血流速度
C.增加血流量
D.增强超声造影效果
E.消除超声造影的副作用
参考答案:A
根据句意及首字母或汉语提示完成单词。
1. Mary has no m____ to buy the book.
2. Mr. Brown works in a h____. He is a doctor.
3. Jim is too y____.He can't go to school.
4. Our teachers work ____(努力地), and we all like them.
5. Don't play in the street. It's ____ (危险的).
作用力和反作用力的关系为()。
A.大小相等
B.作用在同一个物体上
C.方向相反
D.作用线相同