小心均匀加热大试管3﹣5min．请回答问题：

“五一”劳动节是全世界劳动人民的节日,这一节日的设立是对劳动者的尊重和爱戴,这是因为(　　)

①劳动创造物质财富和精神财富　②劳动是人类文明进步发展的源泉　③劳动光荣　④劳动者是生产过程的主体,在生产力发展中起主导作用

用括号中所给单词的适当形式完成下列句子。
 Davy enjoys____ (play) tennis and baseball.
It will be____ (wind) in Sanya tomorrow.
Nobody teaches her English. She learns it by____ (she).
Jackie Chan is a famous____ (act).
 I____ (visit) my aunt on the farm last weekend.
In China, September 10^th is____  (teacher) Day.
— Where is Amy?— She____ (go) to Guilin. She’ll be back next week.
We can see many____ (potato) in the supermarket.
 Sometimes it rains____  (heavy) in Wuzhou in summer.
 My grandparents live on the____ (twelve) floor of a tall building.