_____ the meeting himself gave them a great deal of encouragement.

A．The president will attend

B．The president to attend

C．The president who attending

D．The president's attending

在钢梁底面设有吊杆，其拉力设计值650kN，吊杆通过节点板将荷载传给钢梁，节点板采用双面角焊缝焊于梁下翼缘，h_f=10mm，每面焊缝长度是（）mm。

A．240

B．250

C．260

D．270