义和团运动是 [ ]
A．农民反封建斗争
B．农民反帝反封建斗争
C．农民反帝爱国运动
D．农民反洋教斗争
答案：C
_______, the experiment will be successful.
A．If carefully doing
B．If it done carefully
C．If carefully done
D．If doing carefully
空气压缩机吸气口必须设置什么装置？
