51.dangerous=perilous(very dangerous, hazardous(dangerous, especially to people's safety and health)

　　52.nowadays=currently

　　53.only=unique(the only one of its kind), distinctive;

　　54.stop=cease(if something ceases, it stops happening or existing)

　　55.part=component(the components of something are the parts that it is made of)

　　56.result=consequence(the results or effects of something)

　　57.obvious=apparent, manifest

　　58.basedon=derived fromcan see or notice them very easily)

　　60.quite=fairly