机械制图中尺寸注法的基本规则是什么？
参考答案：
（1）机件的真实大小应以图样上所注的尺寸数值为依据，与图形的大小及绘图的准确度无关。
（2）图样中的尺寸，以毫米为单位时，不需要标注计量单位的代号或名称。
（3）图样中所注的尺寸，为该图样所示机件的最后完工尺寸，否则应另加说明。
（4）机件的每个尺寸，一般只标注一次，并应标注在反映该结构最清晰的图形上。
| 完形填空。 | ||||
| One stormy night, many years ago, an elderly man and his wife entered the lobby (休息室) of a small hotel in Philadelphia. Trying to get out of the 1 , the couple approached the front desk hoping to get some 2 for the night. "Could you possibly give us a room here?" the husband asked. The clerk, a 3 man with a winning smile, looked at the couple and 4 , "All of our rooms are taken, 5 I can't send a nice couple like you out into the rain at one o'clock in the morning. Would you perhaps be 6 to sleep in my room? It's not 7 a suite (套房), but it will be good enough to make you folks 8 for the night." When the couple 9 , the young man pressed on. "Don't worry about me; I'll 10 just fine," the clerk said. So the couple 11 . As he 12 his bill the next morning, the elderly man said to the clerk, "You are the kind of manager who should be 13 of the best hotel in the United States. Maybe someday I'll build one for you." The clerk looked at them and smiled. The three of them had a good 14 . As they drove away, the elderly couple agreed the helpful clerk was indeed exceptional (例外的), as finding people who are both friendly and helpful isn't easy. The clerk had almost forgotten the incident 15 he received a letter from the old man. It 16 that stormy night and enclosed (附上) a round-trip 17 to New York, asking the young man to pay them a 18 . The old man met him in New York, and led him to the comer of Fifth Avenue and 34th Street. He then 19 a great new building there, a palace of reddish stone, with turrets (塔楼) and watchtowers thrusting up to the sky. "That", said the old man, "is the hotel I have just built for you to 20 ." You never know whose heart you may be touching! | ||||
|