【判断题】The activity in the first picture is a task.
【简答题】With the words given in the first picture, complete the statements in the second and third pictures.
【单选题】LC并联谐振回路,当回路的工作频率大于回路的谐振频率时,回路呈( )。
【单选题】带小圆孔的拉杆,在有孔的截面上,孔边的应力急剧增大,这种现象称为应力集中。产生应力集中的原因是(D)。
A.
孔口截面的面积比其他截面的面积要小,因此,根据公式σ=,所以应力增大了
B.
不但孔口截面的面积减小,而且孔口截面的内力比其他截面上的内力要大,故根据公式σ=,应力就急剧增大
C.
由于圆孔很小,孔口截面的面积减小的不是太多,因此起主要作用的是孔口截面上的内力增大了
D.
由于孔口截面尺寸的突然改变,因此改变了该截面上的应力分布,使得孔口附近的应力急剧增大
【简答题】本项目中,我们采用( )实现让数码管分别接收相应数值的目的。
【单选题】In the first picture, what is the man going to do?
A.
He is going to Wuhan to save his relative who have contracted the new coronavirus.
B.
He is going to Wuhan to develop the medicine to cure the people who have infected the new coronavirus.
C.
He is going to Wuhan to help the people who have infected the new coronavirus.
D.
He is going to Wuhan to see his relatives and friends who are free from new coronavirus.
【单选题】How many types of differeces are there in the first picture on the PPT.