牙槽骨骨折可行（）
A.暂时制动
B.牙间结扎
C.颌间结扎
D.切开复位内固定术
E.暂不处理，随访
参考答案：B
用科学记数法表示0.0000909，并保留两个有效数字得（ ）
A．9.1×10-4
B．9.1×10-5
C．9.0×10-5
D．9.07×10-5
—I was ill and I didn't go to school the day before yesterday.
—______ [ ]
A. Don't worry.
B. I'm very sorry to hear that.
C. It doesn't matter.
