简述水准测量必须注意的事项。

While I          that my disability has made me weak and clumsy, it doesn't mean my life is not satisfying.[      ]

A. recommend

B. acknowledge

C. comment

D. reject

食物链和食物网中的各种生物之间存在着______的关系．其中任一环节出了问题，都会影响整个生态系统．正是由于______、______、______的存在，使各种生物与环境成为一个统一的整体．

关于胸骨后前位摄影的叙述，错误的是（）

A.倾斜X线管--使胸椎投影推移

B.采用短距离--使后肋模糊

C.呼吸曝光--使肋骨产生运动模糊

D.短时间曝光--增加背景的运动模糊

E.中心线倾斜30°～40°--心脏投影于胸骨左面

Winning the bid to host the Olympic Games means not only a great honor to a nation ________.    [ ]

A. but a great responsibility        

B. but as well as a great responsibility   

C. as well as a great responsibility    

D. but a great responsibility as well

刚性防水屋面隔离层的做法有（）。

A.麻刀灰

B.纸筋灰

C.水泥砂浆

D.干铺一层油毡

E.混合砂浆