Lecture 25: Conditional Sentence ■1 Definition A conditional sentence(or conditional for short) is commonly composed of two parts conditional clause main clause. Despite the many possible sequences of verb forms in conditionals, the following four types represent perhaps the commonest and the most useful ones I. If you heat ice, it melts. (AF# General conditionals II. If we catch the 10 o'clock train, we will get there by lunchtime (真實假設 Open Present or future conditionals) III. If we caught the 10 o'clock train, we would get there by lunchtime.(虚設假設 Unreal Present or future conditionals) IV. If we had caught the 10 o'clock train, we would have got there by lunchtime.(過去虛設假設 Unreal Past conditionals)
Lecture 25: Conditional Sentence ◼ 1 Definition ◼ A conditional sentence (or “conditional” for short) is commonly composed of two parts: conditional clause + main clause. Despite the many possible sequences of verb forms in conditionals, the following four types represent perhaps the commonest and the most useful ones: ◼ I. If you heat ice, it melts. （真理General conditionals ） II. If we catch the 10 o’clock train, we will get there by lunchtime. （真實假設 Open Present or future conditionals ） III. If we caught the 10 o’clock train, we would get there by lunchtime. （虛設假設 Unreal Present or future conditionals ） IV. If we had caught the 10 o’clock train, we would have got there by lunchtime. （過去虛設假設 Unreal Past conditionals ）
2. Types of Conditional Sentence Conditional Type 1: Truth(General conditionals) 這是一個基於真理( General truth)上的假設,來說及一些不 變定律或習慣性的情況, a Basic form: if-clause main clause present simple present simple a e.g.: If we eat contaminated food, we become ill e.g.: If we don't feel well, we see a doctor e.g.: If we boil water to 100C, it changes into steam Conditional Type 2: Real(Open Present or future conditionals) 真實的假設,是我們最常用的一種。就是說及一些現在發生的 事,可能會造成將來那些結果。 B asic torm Clause an clause present tense future tense
◼ 2. Types of Conditional Sentence ◼ Conditional Type 1: Truth (General conditionals) ◼ 這是一個基於 真理 （ General truth ） 上的假設，來說及一些 不 變定律 或 習慣性 的情況。 ◼ Basic form : if-clause main clause present simple present simple ◼ e.g.： If we eat contaminated food, we become ill. e.g.： If we don't feel well, we see a doctor. e.g.： If we boil water to 100℃, it changes into steam. ◼ Conditional Type 2: Real (Open Present or future conditionals) ◼ 真實的假設 ，是我們最常用的一種。就是說及 一些現在發生的 事，可能會造成將來那些結果 。 ◼ Basic form : if-clause main clause ◼ present tense future tense
e.g.: If it rains tomorrow morning, we will cancel our picnic e.g.: If you are hungry now I will make you some hot cakes e.g. If you want to read the book i will lend it to you 這三句例子都十分普通,但其實 real conditionals可以有幾種改 變,發揮出不同的效果 "wil'" Replaced by"Can/May"作為"應允 a e.g.: You can/may borrow my camera if you want to take some photographs “W” Replaced by“May/ ight/Could”作為表示“可能性 e.g. If the no. 3 signal is hoisted tomorrow morning, the ferry services may/might/could be suspended wI” Replaced by“Can/ Could”作為表示“能力所及” e.g. If you try hard, you can/could learn to use the computer well
◼ e.g.：If it rains tomorrow morning, we will cancel our picnic. e.g.：If you are hungry now, I will make you some hot cakes. e.g.：If you want to read the book, I will lend it to you. ◼ 這三句例子都十分普通，但其實 real conditionals 可以有幾種改 變，發揮出不同的效果： ◼ " Will " Replaced by " Can/May " 作為 " 應允 " ◼ e.g.： You can/may borrow my camera if you want to take some photographs. ◼ “ Will ” Replaced by “ May/Might/Could ” 作為表示 “ 可能性 ” ◼ e.g.： If the no. 3 signal is hoisted tomorrow morning, the ferry services may/might/could be suspended. ◼ “ Will ” Replaced by “ Can/Could ” 作為表示 “ 能力所及” ◼ e.g.： If you try hard, you can/could learn to use the computer well
" should" being used in If- clause以表示"較低可能性" e.g. I don, t think Winkie is going to the party this evening, but if I should see her, I will give her this message 注意:當我們在 main clause用上“ should”,那個“if”可 以刪除。 a e.g.: Should i see her at the party, I will give her your message a Using Present Perfect or Present continuous Tense If- clause以表示不同時態 a e.g.: If it has stopped raining, we can go out now e.g. If you are having dinner now, I will call again later ■任何"建議性"的意思都可用於 main clause e.g.: If you don't feel well, you would better see a doctor you should stay in bed you ought not to be working now why don 't you take a day off would you like me to call the doctor?
◼ " should " being used in If-clause 以表示 " 較低可能性 " e.g.： I don't think Winkie is going to the party this evening, but if I should see her, I will give her this message. ◼ 注意：當我們在main clause 用上 “ should ” ，那個 “ if ” 可 以刪除。 ◼ e.g.： Should I see her at the party, I will give her your message. ◼ Using Present Perfect or Present continuous Tense in If-clause 以表示不同時態 ◼ e.g.： If it has stopped raining, we can go out now. e.g.： If you are having dinner now, I will call again later. ◼ 任何 " 建議性 " 的意思都可用於 main clause e.g.： If you don't feel well, you would better see a doctor. you should stay in bed. you ought not to be working now. why don't you take a day off? would you like me to call the doctor?
a Conditional Type 3: Unreal(Unreal Present or future conditionals UNreal Past conditionals) It is possible but very unlikely, that the condition will be fulfilled a Basic form: if-clause main clause past simple would infinitive Ie.g. I am busy now. If I had time, I would certainly help you e.g. I don,'t have a car. If I had one, i would take you for a ride round the town e. g. i don ' t think it will rain tomorrow if it did (tomorrow ),we would stay at home and do some reading instead Unreal present or future conditionals的變化: Using"were" instead of"was"提供一個嚴肅的風格( formal styie e.g.: If he was/were here now, he would be very glad to see you
◼ Conditional Type 3: Unreal(Unreal Present or future conditionals及Unreal Past conditionals) ◼ It is possible but very unlikely, that the condition will be fulfilled. ◼ Basic form : if-clause main clause ◼ past simple would + infinitive ◼ e.g.： I am busy now. If I had time , I would certainly help you. e.g.： I don't have a car. If I had one, I would take you for a ride round the town. e.g.： I don't think it will rain tomorrow. If it did （tomorrow）, we would stay at home and do some reading instead. ◼ Unreal Present or future conditionals 的變化： ◼ Using " Were " instead of " Was " 提供一個 嚴肅的風格(formal style) e.g.： If he was/were here now, he would be very glad to see you