sign, signal, symbol

　　读一读下面三个句子,看看你能不能分辩出sign, signal, symbol 的不同意义:

　　1. There are no signs of life about the house.

　　2. The railway signal showed that the train could pass.

　　3. White is the symbol of purity.

　　[简析] 1. 这房子没有有人住的迹象。(sign 用作名词, 有 “记号， 手势, 姿势,告示，牌子, 迹象,征兆” 等意义; 作动词用, 有 “签名,做手势” 等意义.)

　　2. 铁路的信号标志显示火车可以通过。( signal 用作名词, 有 “信号，暗号”等意思; 作动词用,意思是 “发信号,用信号表示”)

　　3. 白是纯洁的象征。(symbol作名词, 意思是 “符号, 象征”,其动词形式是 symbolize.)

　　[即学即用] 用 sign, signal, symbol及其正确形式填空:

　　1. She put her finger to her lips as a _______ to be quiet.

　　2. A red lamp is often used as a danger _________.

　　3. The _______ by the road says ‘No Parking'.

　　4. In the picture the tree is the ________ of life and the snake the ________ of evil.

　　5. The policeman _______ the traffic to move forward slowly.

　　6. Please ______ your name here.

　　7. A wedding ring _______ the union of husband and wife.

　　Keys: 1. sign; 2. signal; 3. sign; 4. symbol, symbol; 5. signaled 6. sign; 7. symbolizes.