首拌混凝土空车运转的检查中,检查时间一般为()
A. 2~3min
B. 3~5min
C. 5min
D. 3min
检疫人员进行生猪屠宰检疫时,发现一头猪的膈肌中有黄豆大小的半透明囊泡,泡内充满囊液。泡壁上有一小结节,经光学显微镜下观察为寄生虫头节。该虫体最可能是()
A. 旋毛虫
B. 弓形虫
C. 棘球蚴
D. 肉孢子虫
E. 猪囊尾蚴
作业中断超过(),作业人员再次进入有限空间作业前,应当重新通风、检测合格后方可进入。
A. 30min
B. 10min
C. 1h
If a single cylinder relief valve on a diesel engine lists frequently while the engine is
A. excessively late injection timing for each cylinder
B. incorrectly adjusted intake valve timing
C. incorrectly adjusted fuel injector
D. incorrectly adjusted intake valve clearance