1,极昼现象的形成等等介绍
2,have sb/sth + do
doing
done
的区别与用法
请用英语解释一下,答案精彩可以追加分。
參考答案:1、Polar day In polar regions, the portion of the year when the Sun is continuously in the sky. Its length changes from twenty hours at the Arctic/Antarctic Circle (latitude 66°33' N or S) to 186 days at the North/South Pole.
polar night
The polar night is the night lasting more than 24 hours, usually inside the polar circles. The opposite phenomenon, when the sun stays above the horizon for a long time is called the polar day, or midnight sun.
2、have sb do/doing ---the subject is sb,and do/doing is the movement of sb ,the difference between do and doing is that doing should be a verb that can last for some time,but do can be a verb only for a short moment or can't last.
have sth done ----sth is the object ,done is the past participle.so sth be done is the passive tense.