单项选择题
Before using or operating any equipment, you should first （） its manual thoroughly and understand its contents（）.
A.read/sufficient B.consult/sufficiently C.read/sufficiently D.consult/sufficient
单项选择题 When we say that two objects have relative motion, we mean （）.
单项选择题 The trouble-free life of an engine indicates （）.
单项选择题 General, the best way for replacement of lamp is （）.
