Unit 3 Safety1. Look at this yellow star, Brian and Jenny! 布萊恩、詹妮，看這顆黃色的星星！2. Let me get the ladder for you.讓我給你拿把梯子。3. Dont stand on chairs. 不要站在椅子上。4. Be careful with scissors and knives!小心剪刀和刀子！5. Never smoke because of much pressure!永遠不要因為壓力大而吸煙！1. 定義祈使句是英語中的基本句型之一，用來表達建議、命令、請求、警告、勸告、禁止等語氣。祈使句的主語一般為第_人稱，通常可以_。為了使語氣更加客氣或緩和，可在句前或句末加上_一詞。2. 構成(1)祈使句的肯定形式一般以_動詞或_動詞原形開始，也可以以動詞let 開始。(2)祈使句的否定形式一般在句首加_或_。(3)以let開頭的祈使句：肯定句：Let him come in.否定句：Dont let him come in.或Let him not come in.(4)有些祈使句可用No開頭，表示禁止。No smoking, please. 請不要吸煙。No photos! 禁止拍照！3. 拓展(1)祈使句的反意疑問句祈使句的反意疑問句，若陳述部分是否定句，則附加問句只能用will you。若陳述部分是肯定句，附加問句既可用will you，也可用wont you。lets開頭的祈使句用于提出建議，包括對方，其附加問句用shall we。let us開頭的祈使句表示征求對方許可，其附加問句用will you。Dont do that again, will you?Go with me, will you/wont you?Lets go, shall we?Let us take an exam, will you?(2)祈使句用于兩個重要句型“祈使句and表結果的陳述句”用來敘述肯定的條件。“祈使句or表結果的陳述句”用來敘述否定的條件。注意 這兩個句型都可以改寫為if引導的條件狀語從句。Work hard, and you will pass the exam.(If you work hard, you will pass the exam.)Work hard, or you will not pass the exam.(If you dont work hard, you will not pass the exam.) .單項選擇()1. xx白銀Boys and girls，_ learning and have fun.Akeep Bto keep Ckeeping Dkept()2. _carefully, please! Look at the road sign. There is a school ahead.ADrive BTo driveCDriving DDrives()3. _ patient with him, please. He is only three years old. ADont BBe CIs DDoes ()4. xx渝北_throwing those stones, please.AStop BStops CStopping DStopped()5. xx安徽Hold your dream，_ you might regret some day.Aand Bor Cbut Dso()6.xx濱州I want to be a teacher when I grow up.Work hard，_ your dream will come true.Aor Bbut Cthough Dand. 按要求完成下列各題1. xx達州This warning sign tells us not to pick flowers. (保持句意基本不變)This warning sign says “_ _ flowers”2. xx天水Tell him the truth at once, or he will be angry. (改為主從復合句)_ _ dont tell him the truth at once, he will be angry.3. xx天水Let us go hiking, _？ (完成反意疑問句)4. You should be relaxed. (改為祈使句)_ _， please.5. Dont park here. (改為同義句)_ _！教師詳解詳析【語法探究】1. 二； 省略； please 2. (1)實義；