鼓风机揭大盖检修后，一定要检查进风管内有无杂物的目的是（）。
A.防止杂物在开机时吸入风机内
B.降低进风阻力
C.防止风机噪声
参考答案：A
Liu Zhuiheng , ______ is suspected of setting off an explosion at a tax office on July 30 in Hunan Province , ______ four people were killed and 19 injured , is taken into police custody(拘留) in Changsha in this undated photo.
A．that ; in which
B．that ; where
C．who ; in which
D．who ; which
根据塑料的热行为可分为（）和（）。
