由于声束扩散原因引起的声衰减,可以克服的方法是()
A.降低帧频
B.提高帧频
C.变换探头频率
D.声束聚焦
E.降低探头频率
参考答案:D
Anyone who doubts that children are born with a healthy amount of ambition need spend only a few minutes with a baby eagerly learning to walk or a headp toddler starting to talk. No matter how many times the little ones stumble in their initial efforts, most keep on trying, determined to master their amazing new skill. It is only several years later, around the start of middle or junior high school, many psychologists and teachers agree, that a good number of kids seem to lose their natural drive to succeed and end up joining the ranks of underachievers. For the parents of such kids, whose own ambition is often inseparately tied to their children’s success, it can be a bewildering, painful experience. So it is no wonder some parents find themselves hoping that ambition can be taught like any other subject at school.It’s not quite that simple. "Kids can be given the opportunities, but they can’t be forced," says Jaequelynne Eccles, a psychology professor at the University of Michigan who led a study examining what motivated first-and-seventh-graders in three school districts. Even so, a growing number of educators and psychologists do believe it is possible to unearth ambition in students who don’t seem to have much. They say that by instilling confidence, encouraging some risk taking, being accepting of failure and expanding the areas in which children may be successful, both parents and teachers can reignite that innate desire to achieve.Dubbed Brainology, the unorthodox approach uses basic neuroscience to teach kids how the brain works and how it can continue to develop throughout life. The message is that everything is within the kids’ control, that their intelligence is
malleable
The word "aspirations" underlined in Paragraph 4 refers to ______.
A.ambition
B.caree
C.goal
D.project
男性,45岁,原有胃溃疡病15年,近2个月腹痛节律性消失,服用胃舒平疗效不佳。
若系胃癌,最佳治疗方案是()
A.胃癌根治术
B.胃癌根治术加术后化学治疗
C.介入治疗
D.先进行化学治疗,再行手术治疗
E.静脉化学治疗加中药治疗