通风与空调工程安装完毕必须进行设备单机和系统无生产负荷下的联合试运转调试，调试检查的

看谁写得多。

蚯蚓体壁分泌黏液，保持湿润，有利于呼吸。 （   ）    

Have you ever dreamed of staging a concert,       thousands of people are applauding and appreciating your music?

A．at which

B．when

C．for which

D．which

白细胞有吞噬病菌的作用，血液中白细胞越多越好．______．

腰部最易损伤的韧带是

A．棘上韧带

B．黄韧带

C．后纵韧带

D．前纵韧带

E．椎间韧带