一物体做匀减速直线运动，初速度为10m/s，末速度为2m/s，物体的平均速度为（

风湿性心瓣膜病时最常被侵犯的瓣膜是（）

A.二尖瓣

B.主动脉瓣

C.肺动脉瓣

D.三尖瓣

E.二尖瓣+主动脉瓣

—What does Lily think _        the movie?  

—She loves it.   [ ]

A. at        

B. in          

C. of            

D. on

At the meeting Mr. King didn't say a word from beginning to end, ______? [ ]

A. didn't Mr. King

B. did he

C. did Mr. King

D. didn't he

患者男性，52岁，右眼傍晚出现雾视2个月。检查：右眼视力1.0，右眼周边前房1／3CT，房角功能性小梁开放2／3圆周，右眼底视神经 * * 和视野正常。最恰当的手术方式（）

A.周边虹膜切除术

B.节段性虹膜切除术

C.小梁切除术

D.非穿透滤过手术

E.小梁切开术

一龄鱼种搭配混养要注意哪些问题？。