Unit18 The United States of America知識點總復習教案

32. … , and the insects which lived on these plants died out. 原來靠那些植物衛生的昆蟲也都死了。(p. 47 最后一段第3行)
★die out的含義
(1) (指家族, 物種)死光, 滅絕, 絕跡 these animals have already died out.這些動物已經絕種。
(2) (指習俗，做法)消失，過時 ① the old traditions are dying out. 舊傳統正在消失。② that style of music died out ten years ago.那種音樂十年前就聽不到了。
(3) 作熄滅解，out為副詞。 the fire has died out. 火熄了。
  拓展：die away 消逝，平息，靜下來; die down 平息，熄滅; die for 迫切想要; die from 由于……而死; die off 一個個死掉，絕種
  【注】 注意die out與die away的區別，后者主要指風、聲、光等自然現象逐漸停止、消失。如: ① the wind has died away again. 風又停了。 ② the sound of the car died away in the distance. 汽車的聲響在遠處消逝。
  【注】die out意為“消亡”“滅絕”，而die off則意為“(一個一個)地死亡”。如: ① the leaves of this plant are dying off. 這株植物的葉子正在一片一片地凋謝。② the deer in the forest are dying off from disease. 森林中的鹿正因疾病而陸續死亡。
33. this in turn had an effect on the food supply for wolves. 這樣反過來又影響了狼的食物供應。(p. 47 最后一段第2行)
  ▲in turn意為“依次”“逐個地”“轉而”“反過來”。如: ① theory is based on practice and in turn serves practice. 理論以實踐為基礎，反過來又為實踐服務。② we'll cross the bridge in turn. 我們將挨個過橋。③ the students answered the teacher's questions in turn.學生們依次回答老師的問題。④ the boys were summoned in turn to see the examiner. 男孩們被依次叫進去見考官。⑤ he spends too much time on maths, and this in turn affects the progress of his other subjects.他在數學上花的時間太多，這同時影響他的其他學科的進步。
【注】以上用法中的turn不能用作復數。
【注】 take turns at (或in) doing sth. 意為“輪流做某事”，相當于do sth. in turn。注意兩短語中名詞的單復數。① mary and helen took turns at sitting up with their sick mother. 瑪麗和海倫輪流熬夜陪伴她們生病的母親。② the athletes took turns in singing songs and reciting poems. 運動員們一個接一個地唱歌和朗誦詩。
【注】 turn也可解釋為“短時間的活動”, 相當于a short period of activity, turn在這里作可數名詞用。如: ① i'll take a few hams round the deck before i go to bed. 就寢之前我要在甲板上散一會兒步。② i'll take a turn at the oars now if you want a rest. 如果你要休息，我來劃一會兒漿。
拓展：take one's turn 輪班(做某事); take turns 輪流(做某事); by turns 輪流; on the turn 將好轉