单项选择题
As a subject-centered language, Chinese tends to use animate things as the subject, usually a person. （ ） A. 对 B. 错
单项选择题 为防止着火与爆炸，关于活塞式空压机油的管理，描述错误的是______。
单项选择题 法兰的密封原理是当压力介质通过密封口的阻力降大于密封口两侧的介质压力降时，介质就被密封住。（ ）
单项选择题 -Where is Li Lei? -He ___ Shanghai. A. has gone to B. has been to C. went to D. goes to
