The professor said he wouldn’t attend the opening ceremony ____.

A．unless was invited

B．until inviting

C．without inviting

D．if not invited

( )是控制挖槽精度的主要构筑物，它应建于坚实的地基之上，开能承受水土压力和施工机械设备等附加荷载，不产生位移或变形。

A．导墙

B．支护

C．坡板

D．壁护