感光作用属于（）
A.化学特性
B.生物效应特性
C.热作用
D.荧光作用
E.电离作用
参考答案：A
We're still at the airport. If it weren't for the delayed flight, we _____ the concert right now. [ ]
A. can be enjoying
B. must have enjoyed
C. would be enjoying
D. should have enjoyed
牙髓失活法最严重的并发症是
A．均不正确B．急性根尖炎C．化学性骨坏死D．封药后疼痛E．急性牙髓炎
