心脏听诊时,主动脉瓣的关闭所引起的振动,标志心室舒张期开始的心音为()。
A.第一心音
B.第二心音
C.第三心音
D.第四心音
E.连续性杂音
参考答案:B
Of the 2000 stock investors last month, 90% was found in financial knowledge. [ ]
A. surveyed; lacking
B. having been surveyed; to lack
C. surveyed; lacked
D. to have been surveyed; lack
叶克斯—道得生定律说明了当作业愈复杂时,动机的激奋水平应( )。
A.偏低
B.偏高
C.适中
D.无关二、填空题