He never ________ no matter how many difficulties he has.

A．gives up

B．gives in

C．works out

D．goes away

波纹管补贴工具连接顺序自上而下为：滑阀、震击器、水力锚、液缸、止动环、加长杆、安全接头、弹性胀头、刚性胀头、导向头。