Testing of plastics articles ; determination of the effect of internal pressure on hollow objects by long - time test 塑料制品的试验.长时间试验内部压力对空心物体作用的
2.
How often should you test lifeboat engine ? who takes charge of the operation ? who takes of maintenance and repair work 您多长时间试验一次救生艇机？谁负责操纵艇机？谁负责维护和修理艇机？
3.
One week interval . sms requires that every crew on board is capable of operating it . the fourth engineer must take charge of maintenance and repair work 您多长时间试验一次救生艇机？谁负责操纵艇机？谁负责维护和修理艇机？
