主要用于乳牙期、替牙期以矫正牙齿因素为主的前牙反胎的是
A．上颌双侧胎垫矫治器B．带环C．Nance弓D．箭头卡环E．舌习惯矫治器
参考答案：A
口腔主要的生态系不包括（）
A.颊上皮生态系
B.舌背部生态系
C.龈上牙菌斑生态系
D.龈下牙菌斑生态系
E.腭上皮生态系
One advantage of using price-to-book value multiples for stock valuation is that:（）
A. most of the time it is close to the market value.
B. it is a stable and simple benchmark for comparison to the market price.
C. accounting standards for assets are always consistent across firms.
