The mayor of Zhuanghe City was ordered to resign because of his refusal to ________ when more than 1000 villagers got down on their knees before the city government office building, begging for his help.

A．break up

B．link up

C．fill up

D．show up

当襟缝翼构型为1+F情况下飞机空速达到210节后会发生什么（）

A.襟翼自动收回到0位，新的襟缝翼构型为1

B.襟翼自动伸出因为空速过高

C.迎角保护被衔接因为空速过高