1)can could 表示能力;可能 (过去时用could),
只用于现在式和过去式(could)。be able to可以用于各种时态。
They will be able to tell you the news soon. 他很快就能告诉你消息了。
2)只用be able to
a. 位于助动词后。
b. 情态动词后。
c. 表示过去某时刻动作时。
d. 用于句首表示条件。
e. 表示成功地做了某事时,只能用was/were able to, 不能用could。
He was able to flee Europe before the war broke out.
= He managed to flee Europe before the war broke out.
注意:could不表示时态
1)提出委婉的请求,(注意在回答中不可用could)。
--- Could I have the television on?
--- Yes, you can. / No, you can't.
2)在否定,疑问句中表示推测或怀疑。
He couldn't be a bad man.
他不大可能是坏人。
报告指出 中国每年70万人因酒丧命
关于爱情的最佳建议
国际英语资讯:Remittances to Mexico increase 10.3 pct in July: central bank
国内英语资讯:Xi says China to implement eight major initiatives with African countries
IBM新发明:只要你困了,无人机就会自动倒咖啡
国内英语资讯:China, South Africa agree to lift ties to new level
朋友不需要太多,只要知心
美国的劳动节
吃东西声音大令你抓狂?你可能患有恐音症
国际英语资讯:Security check trays one of largest risks to health at Helsinki airport
体坛英语资讯:China beat UAE 2-1 to reach final 16 in Asian Games mens soccer competition
中国承诺对非援助新增600亿,不附加政治条件
国内英语资讯:President Xi meets UN chief
体坛英语资讯:Chinese fencers dominate womens individual sabre at Asiad
国内英语资讯:China has 32 airports handling over 10 million passengers annually
Can Online Course Replace Traditional Course? 网络课程是否可替代传统课程?
国际英语资讯:Immigrant family use fake passports to seek asylum in Norway: report
瞠目结舌! 50种驱蚊产品竟无一有效
国际英语资讯:Liverpools iconic building engulfed by fire
国内英语资讯:Chinas top legislator meets Ethiopian prime minister
Is Modern Technology Creating a Single World Culture? 科技在创造单一文化世界吗?
国内英语资讯:Senior CPC official meets Angolan president
国内英语资讯:Chinese vice premier meets Djiboutian president
国际英语资讯:Spain asks EU to step in after U.S. decides to end assistance for Palestinian refugees
特斯拉宣布放弃私有化 大多数股东支持
国内英语资讯:Full text of Chinese President Xi Jinpings speech at opening ceremony of 2018 FOCAC Beijin
报告显示 中国继续保持出境游消费世界第一
双语阅读:I Have a Dream(一) 我有一个梦想(一)
娱乐英语资讯:Romanias Golden Stag Festival ends with Albanian singer winning trophy
英语阅读:继苹果后,亚马逊成第二家市值突破万亿的公司
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |