数字化彩色超声的关键技术是()
A.宽频探头
B.二次谐波成像
C.数字化波束形成器
D.多道电子开关选择发射及接收的振子
E.预置多种优化检查条件
参考答案:C
Doctors strongly recommended that my father _____ more exercise regularly instead of sitting still before a computer all day long.
A.takes
B.take
C.took
D.had taken
下列疾病中适宜开展二级预防的是()
A.心肌梗死
B.色盲
C.胰腺癌
D.肺结核
E.麻疹