Theknockoccurringwhenacolddieselengineisstartedandcontinueswhilerunningatlowspeed,butstopswhentheenginereachesnormaloperatingspeedandtemperature,is().
A. causedbyretardedinjectiontiming
B. causedbyamechanicaldefectinonecylinder
C. causedbyhighfuelinjectionpressures
D. normalfortheseconditions
Thebrokenmagentalines(longandshortdashes)inandaroundMobjackBayindicate().
Amphibioustrainingareas
B. Groundsfordredgespoil
C. Fishtrapareas
D. Gunneryexerciseareas
脊索动物门分三个亚门,包括下列哪一个()
A. 节肢亚门
B. 半索亚门
C. 脊椎亚门
D. 棘皮亚门
电话服务台应答时限指自用户拨号完毕听到回铃音至话务员(包括电脑话务员)应答所需要的时间,应答时限不得超过()
A. 10s
B. 15s
C. 20s
D. 25s