(2013·辽宁六校高三联考)Have you ever seen any trees ________ leaves were black because of the polluted air?

A．whose

B．that

C．which

D．who

一患者戴用全口义齿患者在左侧方咬合时，平衡侧基托翘动、脱落，其可能原因是（）

A.正中牙合不平衡

B.侧方不牙合平衡

C.前伸不牙合平衡

D.垂直距离过高

E.义齿固位差