操作系统的特性主要有（）等四种。 A.并发性、共享性 B.诊断性、同步性 C.控制性 发布时间：2017-07-29 15:07 │ 来源：www.tikuol.com 题型：多项选择题 问题： 操作系统的特性主要有（）等四种。A.并发性、共享性B.诊断性、同步性C.控制性、虚拟性D.虚拟性、异步性
题型：多项选择题 Su Hua is studying at Cambridge, UK. She has bought a bicycle and is worried about security（安全）. Her friend, Kate, found this article and sent it to her.IntroductionA lot of crime is against bicycles. About 150,000 bicycles are stolen every year and most are never found. You can prevent this happening by following a few careful steps.Basic SecurityDo not leave your bicycle in out-of-the-way places. Always lock your bicycle when you leave. Secure it to lampposts or trees. Take off smaller parts and take them with you, for example lights and saddles（车座）.LocksGet a good lock. There are many different types in the shops. Buy one that has been tested against attack. Ask for a recommendation from a bike shop.MarkingSecurity marking your bike can act as a deterrent to a thief. It can also help the police find your bicycle. It should be clearly written and include your postcode and your house or flat number. This will provide a simple way to identify your bicycle.RegistrationThere are a number of companies who will security mark your bicycle for you. They will then put your registration number and personal details on their computer database. Then if your bicycle is found it will be easy to contact you.FinallyKeep a record of the bicycle yourself: its make, model and registration number. You can even take a photograph of it. This will prove the bicycle belongs to you.小题1:Which part of the text gives you information on how to lock up your bicycle when you leave it?A．Locks.B．Marking.C．Registration.D．Basic Security.小题2:The underlined phrase “act as a deterrent to a thief” means .A．help you recognize your bikeB．help the police find your bicycleC．stop someone stealing your bicycleD．stop you worrying about your bike小题3:The article advises you to keep a record of your bicycle .A．in the bike shop and your computerB．in a police station and a security companyC．in a security company and your universityD．by yourself and in a security company小题4:The main purpose of this article is .A．to tell you what to do if your bicycle is stolenB．to suggest ways of keeping your bicycle safeC．to give you advice on where to buy a good lockD．to say why you shouldn’t keep your bicycle in a quiet place 查看答案
题型：多项选择题 Now the air in our city is ______ than it used to be. Something must be done to stop it.A．goodB．badC．worseD．better 查看答案
题型：多项选择题 下列各组物质的鉴别方案中不正确的是（ ）A．蒸馏水、澄清石灰水（分别取样于两支试管中，通入二氧化碳）B．酒精、白醋（闻气味）C．空气、二氧化碳、氧气、氮气（分别伸入带火星的木条）D．二氧化锰、氯酸钾（观察颜色） 查看答案