牙齿釉质表面呈淡黄色的原因是

A．釉质钙化不良

B．釉质缺损

C．釉质本身呈淡黄色

D．釉质钙化程度高，-不能透过牙本质的颜色

E．釉质钙化程度高，透过牙本质的颜色

Compared with his sister, Jerry is even more_____to, and more easily troubled by , emotional and relationship problems.

A．sceptical

B．addicted

C．available

D．sensitive