Module 5 Rules and suggestionsUnit 1You must keep to the path.1 ． Before we can enjoy ourselves on the Great Wall, there are afew rules and suggestions. 在游览长城前，还有一些规定和建议。can 是情态动词，意为“能够”，表能力。如：He can speak Japanese. 他会讲日语。can 与 be able to(1)can 表示过去或现在“能够”时，可以与 be able to 通用。如：He could/was able to run very fast when he was a boy. 他小时候就能跑得很快。(2)can 通常只用于一般现在时或一般过去时，而 be able to 可用于各种时态。如：He has not been able to come since he got hurt. 自从受伤以后，他就一直未能前来。(3) 在表猜测时，只能用 can ，不能用 be able to 。如：That can't be your bag. 那不可能是你的书包。①Susan is good at English and she ________ sing Englishsongs.(2010 年福建龙岩 )A ． needB ． mayC ． canC 题意：苏珊擅长英语，而且她会唱英语歌。 can 表示能力，意为“能够”。A ． can'tC ． won't be able toB ． couldn'tD ． wasn't be able toC 由时间状语“ in two hours” 可知谓语时态应用一般将来时； can 和 be able to 都可以表示“能够”，但是 can 通常只用于一般现在时或一般过去时，故答案选 C 。②The car breaks down, so we ________ get there in two hours.2 ． You mustn't walk along the edge because you might fall andhurt yourself. 禁止沿着边缘走，因为你可能会摔倒而伤着自己。(1)mustn't 是情态动词 must 的否定形式，表示“禁止”。如：Elevators mustn't be used when there is a fire.当火灾发生时，千万别搭乘电梯。(2)might 也是情态动词，表示一种把握不大的猜测，意为“ 可能”。如：I don't know her.She might be the new neighbor.我不认识她，她可能是新邻居。must 引导一般疑问句时，其肯定回答用“ Yes, ...must.” ；否定回答用“ No, ...needn't./No, ...don't/doesn't have to.” ，而不能用“No, ...mustn't.” 。如：—Must I finish the homework first?我必须先完成家庭作业吗？—Yes, you must. 是的，必须。—No, you needn't/don't have to. ...
