人工后牙半解剖式牙尖斜度为（）
A.0°
B.10°
C.20°
D.30°
E.40°
参考答案：C
判断下面的移项对不对．若不对，错在哪里？应当怎样改正？
（1）从7+x=13，得到x=13+7；
（2）从5x=4x+8，得到5x-4x=8．
Be sure to let Tom know the truth as soon as he ______. [ ]
A. will arrive
B. was arriving
C. arrives
D. arrived
