车轮常见故障有车轮磨耗、裂纹、轮毂松动、踏面擦伤、踏面剥离和（）。
参考答案：局部凹入
— I’m very tired these days because of preparing for exams.
— Why not _____ music? It can make you _______.
A．listen to; to relax
B．listen to; relax
C．to listen to; relax
D．listening to; to relax
腭前神经阻滞麻醉时出现恶心或呕吐，可能是由于
A．注射点过高 B．针尖刺入过深 C．针尖刺入过前 D．针尖刺入过后 E．麻药注射入血管内
