Unit 1 Food matters Section 3 Grammar and usage 导学案（含答案）-译林版(2019)选择性必修第一册

Unit 1 Food matters Section 3 Grammar and usage To infinitives as subjects and predicatives 1. Identify the use of to infinitives as subjects and predicatives； 2. Work out the rules of to infinitives used as subjects and predicatives； 3. Use the right forms of to infinitives to finish tasks of rewriting sentences and writing a thank you note； 4. Apply to infinitives in new situations. 定义(Definition)：动词不定式是英语动词的非谓语形式之一，形式上由“to＋动词原形”构成。动词不定式仍保留着动词的部分特性，可以跟宾语和状语构成动词不定式短语，有时态和语态的变化。句法功能上，动词不定式(短语)与名词、形容词或副词作用类似，在句子中可以充当主语、表语、宾语、定语、状语、宾语补足语等成分。 Ⅰ 用横线画出下列句子的动词不定式部分 1. To talk to a friend sincerely when something unpleasant happens is very important. 2. It was a great honour to be invited here today. 3. It is necessary for us to make some good friends. 4. She pretended not to see me when I went past. 5. We think it important to master a foreign language. Ⅱ 观察以下句子，分析动词不定式在句子中所充当的成分 1. Not that long ago, my first thought at mealtimes was to eat at a restaurant. 2. To eat out was also a social activity, allowing me to enhance the relationship with my friends. 3. There are a variety of recipes in the app to choose from. 4. When I picked a popular recipe and gave it a try, I discovered that it was not that difficult to make a simple and tasty dish. 5. My plan is to invite my friends over at the weekend and show them my new found skills. 动词不定式的时态和语态 语态 时态 主动 被动 一般式 to do 1. _____ 进行式 2. _____ 完成式 to have done 3. _____ 动词不定式做主语 1. 动词不定式做主语时，一般表示具体的或一次性的动作。做主语的不定式有时态和语态的变化，且谓语动词通常用单数。例如： To finish this job in one day is impossible. 要在一天之内完成这项工作是不可能的。(表示具体的情况) 【注意】 在很多情况下，做主语的动词不定式都可以用动名词替代，但表示某些具体情况，或表示较强烈的对比，或在某些固定说法中时，通常不用动名词替代。例如： To know everything is to know nothing. 样样皆通，样样稀松。 2. 若不定式太长，则往往用it代替不定式做形式主语，不定式移至谓语之后，以使句子结构平衡。其常见句型有以下4种： (1) It＋be＋形容词＋(for/of sb) to do sth: It is very interesting to play in the snow in winter. 冬天在雪地里玩是很有趣的。 (2) It＋be＋名词＋to do sth: It is a great honour to hear you speak so highly of me. 听到你这么夸奖我是我莫大的荣幸。 (3) It takes (sb) some time to do sth: It takes ten years to grow trees, but a hundred years to rear people. 十年树木，百年树人。 (4) It made sb＋形容词＋to do sth: It made me relaxed to know that I have passed the exam. 了解到我通过了考试，我感到很轻松。 动词不定式做表语 1. 动词不定式做表语，可以说明主语的具体内容，还可以表示目的、结果、安排、命令、决定、劝告、意愿等，其主语通常为task、aim、purpose、wish、dream、duty、plan、hope、job、problem等名词，或是what引导的名词性从句。不定式做表语时，主语和表语有时可以交换位置，其意思不变。例如： I've had many dreams ... ...